Disabling automatic new versions in R9 WIP grays out in R8

Downloaded the new R9 WIP and unchecked the automatic downloading option when installing it. Now that seems to have ghosted R8’s Enable Updates, which is a change I didn’t want.

I then set enable_automatic_updates in the registry for R9 to 1. It was already 1 for R8.

Edit to ask:
1: How do I re-enable updates in Rhino 8?
2: How do I avoid affecting R8 when installing or modifying R9 WIP?