I have installed the brain 9 beta (version 188.8.131.52).
Weird observation: When I start it, it opens 2 (!) instances of the application in Windows.
Anyway, when I choose 'Import' from the File menu, and then choose 'Select File...' to open a brain 8, I get this message:
This brain has already been imported. If you have made change in TheBrain8 and wish to integrate them:
1. Sync this brain from TheBrain 9
2. Delete the local copy of this brain.
3. Reimport the version 8 copy of this brain
4. Sync with the server again.
It doesn't make sense to me.