Check out all the schools and train at the one that seems to suit you the best. I train in shotokan and really enjoy it but I've always fancied having a go at kyokushin for the high level of physical conditioning they practice. And, yes, be wary of 8th and 9th dans! Especially if they're fairly young (by which I mean 40-odd years old). 8th and 9th dans are usually people who've made a pioneering contribution to karate. People like Hirokazu Kanazawa, Steve Arneil, Taiji Kase, Keinosuke Enoeda etc If someone's claiming that kind of rank, they need some mighty credentials to back it up!