OK, I hope there is a simple answer for this question.
I still have 8 speed drive train, mostly shimano STX-RC.
In trying to lighten the load Ive bought new cranks and BB, Race Face Prodigy XC, and SRX.
I checked with the LBS when I bought them, and they assure me that there is no problem using 9 speed front chainrings with 8 speed chain / rear cassette.
However, Race Face's website makes some claim of incompatability.
Ok who's blowin smoke up you know where....?