Silent One wrote:
...OS 9 software...Logic etc...
Don't know about Logic, but I have an old version, I think v2.0, of Cubasis VST for Mac OS 9, Steinberg has a user forum for the Cubase VST 5.0 PC/Mac OS 9 audio/recording studio software here if you are interested:
http://www.cubase.net/phpbb2/viewforum.php?f=8&sid=32697c0b95ca78c5d610b67270fc4 a90
I am not sure if those older versions were released in a dual Mac/PC format like the current versions of Cubase are now, you might need to find the Mac specific version of Cubasis VST, not sure when they started shipping in the dual-format package, but my v2.0 is Mac only. Not sure if you can find those in stores or on-line anymore, may be hard to find. They require booting into OS 9, not Classic mode.
http://namm.harmony-central.com/SNAMM01/Content/Steinberg/PR/Cubasis-VST-2.html
Pangea still has some of their old OS 9 games available, they may require pretty high-end CPU/video cards:
http://www.pangeasoft.net/index2.html