Well you really should not be using 8 cogs in each chain ring for a 9 speed casette. That just results in too much cross chaining. Shimano says you can do it, but I'd do it only if I was in a position where I didn't want to shift the front deraillleur under load.

You could do that but really you should be shifting the front rather than trying to use all those cogs with every ring. 9 speed triple has only 15 non-redundant gears anyway.