I would suggest strongly that you go for a 4x5 camera instead of 6x9. You get the benefit of more film, plus it's a standard size. The only benefit to 6x9 I can see is that the film (in 120) is quite cheap... but that's because it's really a medium format camera. And if you like, you can put 6x7, 6x9 and 6x12 rollfilm holders on a 4x5 camera, just make sure it has a graflok back.
Have you had a read of the LFPF front page? If not, go do that now; it will take a couple of days.