Balanced, 9-player setups for Bang!
The problem with larger games in Bang! is that they tend to be unbalanced by the way the game is played. In a 7 or 8 player (in 6 also really) it is very easy for players to be killed before they get a turn. Depending on what character you get and the cards everyone has it is possible that there is nothing that can be done to prevent yourself from being eliminated before your turn. And this is something that would only be magnified in a 9 player game.

From the very fact that it is very possible for people to be eliminated from the game before they had a chance to play I would call it unbalanced.

That is not even mentioning the fact that in the standard rules for 8 players that there are two renegades who are working against each other. As a quick example if an 8 player game comes down to the sheriff, and both renegades one of which accidentally kills the sheriff the game ends with the outlaws winning even though they had all been eliminated.