Was just going to chime in with that also. The only macs that can boot OS 9 have USB 1.1 hardware. DOES work, just very very slow. USB hard drives and flash drives work.
Only works on certain imacs and iirc a few ibooks. Either way you can't upgrade the USB by adding a 2.0 card. So, no joy.
4 yrs ago I would have loved to have found an affordable large firewire flash drive, but Kanguru was the only brand going and they made theirs with solid gold enclosures apparently. Small wonder they never caught on...
