wow...in our area you would have to be a 7 in 8 ball if you are a 9 in 9ball. Can't have more than a 1 sl difference except in the 7/9 case. Example, if you are a 5 in 8 ball, you can be a 4, 5, or 6 (tops) in 9 ball, and vice versa. I can see how someone could be better at one game than the other, but they (local LO) probably wouldn't allow 6/9....
BTW, I had a teammate (8 ball) who was a 4, but when he got raised to a 6 in 9 ball he was automatically raised to a 5 in 8 ball (even though his record didn't show that he should be).