I'm looking at these bikes too. I have a co-worker (in his mid-20s) who's owned both the CAAD8 and CAAD9. He's a cat 3 sprinter and I look to him for first-hand advice these days that I'm in the market for a road bike. He says that the CAAD9 he has now is a little bit stiffer, a little bit twitchier and a little bit more responsive than the CAAD8 he had. Both are definitely racing bikes. He's only had the CAAD9 a couple of months, and I believe he's won a few races with his CAAD8 last year.