I cannot speak to the proper title for any given style other than my own. Our founder, Shimabuku Tatsuo, is referred to as sÅke. There has been a lot of argument over the proper use of that term, and I'm not going to argue with anyone who thinks they know better what the term sÅke means. We use it to mean 'founder of the style'. So, we might say Shimabuku, SÅke to refer to him.
Hey, Bill.
Understanding that you don't want to argue, for the benefit of others, I'm going to point out a bit about the title "soke" here.
It does not, in any way, shape, or form, now, or ever, have the meaning of "founder". It never has. The term itself means "head of the family", and is typically a lineal title used to describe the successors to a tradition/line, originally referring to the legal ownership of a particular methodology of an art form, especially as it related to commercial usage, instruction, and licensing of the art form in question. Beyond that, there are a number of both Confucian and Buddhist ideals and concepts that are contained in the title itself.
Within martial arts, it's usage is relatively recent (early/mid Edo period... essentially 17th-18th Century), with it's more common usage being largely 20th Century. This is primarily due to that commercial aspect I referred to before... it's original ideal was to control the licensing of exponents and instruction single arts in a domain... in other words, if you wanted to study Kabuki in a particular domain, there was one person who was in charge of the development and instruction of Kabuki... same with Chado (tea ceremony), same with Ikebana (flower arranging), and so on. That meant no real competition from rival schools, and there would be certain traits that would identify the art of a particular domain as opposed to others... with martial arts, though, this approach simply doesn't work. While you can aim to retain a single approach to flower arranging as the "domain's form", with martial arts, whoever could develop a better technology could teach it if they could find students... so the idea of having only one person controlling the spread and licensing of "martial arts" in a domain was impractical on a number of levels. Instead, each school would have their own single person in charge of licensing for that school... which would become the adoption of the soke, or iemoto, practice.
Even today, there are Iemoto (soke) in many of these traditional arts... but with the end of the domain (feudal) system of governance, they are not the same as they once were, with many of these regional approaches being either incorporated into others to make more "generalised" approaches, or simply lost to time. Martial arts are one of the only areas it still remains, somewhat ironically preserving a more accurate form of the soke system, despite not really being applied the way it was originally constructed (and not being something it applied to). In fact, the closest martial art (Japanese) model that matches the older commercial-based application of the soke/iemoto approach is actually the Kodokan (Judo), who oversee all aspects of Judo worldwide... but they don't use the title, as they consider it applying only to the older, traditional arts, and the Kodokan's Judo is a move away from those approaches.
When it comes to Shimabuku-sensei, could he be referred to accurately as "soke"? Yes, he could... as he was the one person in charge of licensing, teaching, and so forth, for Isshin Ryu karate. However, the usage of it to mean "founder" would be inaccurate... the term afforded a founder of a ryu-ha is ryuso... pretty literally "head (fount) of the style/system". Can the founder also be a soke? Yes... but it's not often used to describe them until the school is in it's second generation at least. The title of "ryuso" actually puts them separate to the line of soke... in a sense that soke are the ones whose job it is to preserve and protect the work and efforts of the ryuso themselves. But, retroactively, they can often also be considered the first-generation soke... so using the term isn't "wrong", just defining it as "founder" is.
Other than that, in our style, a person could be referred to as 'sensei' after earning their third degree black belt. Other titles, other than sensei, are awarded but not assumed to be automatically given with rank. A person might be a renshi, kyoshi, or hanshi along with their higher ranked black belt, or they might not. Being a 9th Dan, Hanshi, is different than being a 9th Dan. They are titles and not ranks.
It's interesting that you afford a particular rank requirement to the term "sensei"... really, it's not a title in any formal sense of the word, and more a term of respect for the relative position of another to yourself. All it really means is "someone more senior than yourself" (literally: one who was born earlier/before), and is used for anyone from kindergarten teachers to university lecturers, to doctors, to politicians, and can be used for anyone in a more senior position to yourself (such as a boss at work, although you'd often use more formal titles for their specific positions). I've seen a number of cases, mostly Western, where there is an attempt to "formalise" the term sensei as a title that is earned at a particular rank (most often shodan, but can be others), but most Japanese will just be confused by that, ha!
When it comes to the other titles given there (renshi, kyoshi, hanshi), they often have a far more official status and set of requirements... albeit somewhat vague in how they can be awarded. In simple terms, they are different titles referring to levels of teaching authority. They were first developed for use within early Kendo by the Dai Nihon Butokukai, and later got adopted by the Zen Nihon Kendo Renmei, it's direct successor, as well as various arts under the Nippon Budokan's perview (karate, judo, aikido etc). Each of the three teaching titles has a minimum requirement of both grade and age, however simply attaining the rank (dan) is not a guarantee that you also then get awarded the shogo title... as Bill said, you could be a 9th Dan Hanshi, or a 9th Dan (without Hanshi), and the Hanshi would technically be the senior, despite it not being an actual "rank", so to speak. Interestingly, though (just because of the example given), we should note that, in the ZNKR, the effective highest dan grade is Hachidan (8th Dan), as of the year 2000... so any art that has a "9th Dan Hanshi" has most likely awarded it themselves, also adopting this shogo method, rather than from the association (ZNKR) that is genuinely in charge of them.
There are other styles, but not typically used in my organization. I seldom hear much about titles at all, other than 'sensei' and occasionally 'master' or 'grandmaster'. The latter two are not awarded, and one never refers to themselves as sensei, master, or grandmaster. It is what one is called by others. I call my sensei, sensei. He prefers it, even though others from outside our dojo frequently call him master or even grandmaster. As a 9th Dan Hanshi, he is entitled if anyone is, but he still likes to be called 'sensei'.
The idea of not being addressed by these titles is also very much the way it is done. You would have the titles on your name-card (like a personal business card given out to friends and associates with your personal details on it), on any certification you sign, and in formal usage, but rarely would you address someone by the title. At most, the title would be used to refer to an individual to a third party ("Did you see what Nishioka-kyoshi was showing last week? Quite different to Toyama-hanshi's approach!"), but not to the person themselves... in the majority of cases, the most common "to the face" title would be sensei, as Bill says.
When it comes to other titles, there are Shihan, Shihan-dai, Jun-Shihan, Shidoin, Fuku-Shidoin, Shidosha, Shidoshi, Sempai, Kohai, Monjin, Nyumonsha, and more used by various groups/ryu for differing reasons... Shihan, for example, is often a more unofficial title that is used to precede the awarding of shogo titles (in other words, it comes before renshi), however in arts such as Aikido, or the Takamatsuden arts (Bujinkan, Genbukan etc), it is used to describe a senior teacher (where the shogo titles aren't used). Shidoin, Shidosha, and Shidoshi all basically just mean "teacher" (whereas Kyoshi, often rendered as "teacher", has more of the meaning of "professor"... in regular Japanese life, if you are a teacher, then in describing yourself, kyoshi is the more common term to use... you wouldn't introduce yourself and say "watashi wa Eigo no sensei" [I am an English language sensei], you would say "watashi wa Eigo no kyoshi" [I am an English professor/teacher]), with the latter being coined by Hatsumi of the Bujinkan, based on the other terms. Sempai and kohai simply refer to your relative position to others (sempai if you've been doing it longer than someone, kohai if you've been doing it less... so pretty much everyone is both sempai and kohai at all times), monjin, nyumonsha etc are terms used for members, with many others also applied (kai-in as an example). I could go on, but the point is that such titles are often simply applied in-house in the way the particular school wants to use them, and may be taken from, or shared with other groups... or be pretty much unique.