My Visor syncs with my Powerbook 667 just fine. I am using the latest beta version of Palm Desktop, the USB connection, and a Visor Platinum.
The only bugs I can think of are 1) make sure classic isn't running, and 2) once you sync with OS X, don't sync in 9 again.
If you have already tried all this and it isn't working, give some more info. Have you ever been able to sync? Can you sync with other computers? Are you running 10.1.3?