We are currently working on the 3DConnexion support in the Rhino 9 WIP (on both Windows and Mac). Yes, things are quite broken on the Mac at the moment (this is temporary).
Our thinking on this is evolving as we get feedback from users and we’re currently exploring ways to support both the “old way” (which was quite poor on Mac, but some users still liked it) and the new (where everything is controlled from the 3DConnexion driver). We’re not settled on anything yet, but this feedback helps.
We apologize that the Mac side is (more) broken at the moment. It’s only temporary …hence the “Work-In-Progress” part of the WIP. Stay tuned.