I just thought I would share that I upgraded from 8.5 to 9.0 today, and eveything appears to be working just fine. None of my plugins or VSTs were blacklisted. Cubase 9 doesnt support 32bit plugs anymore, so keep that in mind if you upgrade. Steinberg forum showed a number of people running in to that issue.
VEP Instances seems to load much fast when I opened an old 8.5 template project. However, I have moved to just running VEP6 on local host.
First impression of Cubase 9... I'm liking it.