The beige G3 is listed as compatible with OS 8 through 9.2.2. As I remember, OS X in any version wants built-in USB before it will install. Also, OS 9 wants a lot more RAM that 8.X so you might want to check that out before you upgrade.
Badger
PS: I just saw a reference to a utility called XPostFacto that can install OS X on some older, unsupported machines like the beige G3. It's at: http://eshop.macsales.com/osxCenter/XPostFacto. Be sure to check the documentation for details.
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