I finally got around to installing OS 9 on my 1.42 GHz Mac Mini (1 GB RAM). Before I installed it, I found an M-Audio Transit USB for sale on eBay (the one I found was, thankfully, never removed from the box, so the driver CD and other CDs were included).
Fortunately, I have had no mouse freeze-ups, and the M-Audio Transit USB works as a sound device. I ran Reason 2.5 and heard the sound clearly through my headphones. The computer runs OS 9 so, so well! In fact, it runs just as good as my Mac MDD.
My next step is to remove the original hard drive from the Mac Mini, acquire an mSATA to 44 pin IDE adapter, plug an mSATA drive into it, and run OS 9 on that drive.
You guys are an excellent community! You gave my G4 Mac Mini a new life! I was very dissatisfied running OS X 10.4 on it. But OS 9, holy moly, it runs like a dream!
Thank you so much!