I'd like to get USB working on this machine. I have a USB card that works in OSX, but not 9.1. Also I tried installing the USB driver off the OS 9 disc but it says it's not compatible with my system. I extracted the extensions but it didn't work.
Make and model of the USB card might help. You can only use USB 1.x speeds in OS 9 even if you get a compatible card. I have a USB card in my 8500 for over a decade now, they are quite handy to have.
From my experience, any PCI USB 1.1 card will work, but it's a 50:50 success rate for PCI USB 2.0 cards (which run at USB 1.1 speeds under OS 8/9). If they don't work out of the box with Apple's generic USB drivers, they probably never will.