I do confirm I was able to use an Edirol PCR-300 to control Koblo, CellSynth, etc, in my Powerbool Pismo running OS9 today.
I used the PCR driver package from Roland, but I had to have BOTH OMS and FreeMidi active in order to make it work. OMS alone would crash all the time, and FreeMidi would not control applications that require OMS. FreeMidi prefs must be configured with "use OMS when available" and "always load at startup".
Programs must use PCR-1 as input in order to receive MIDI notes.