Hi, conspiracy -
Welcome to Apple's Discussions.
The more recent versions of that keyboard state in the description in the Apple Store that they need OSX.
However, some of the older ones will work fine in OS 9 provided that the extension HID Library is enabled in Extensions Manager.
There are some additional ways to work around that issue using items provided in the Eject Extras folder on some OS 9.1 and later Install CD. If you can't locate that, you can get that here -
Eject Extras