You asked
Can I adapt the tamron sp 85mm f 1 8 di vc usd to canon rf?
The Tamron SP 85mm f/1.8 Di VC USD is listed on this site for Canon EF and Nikon F only. I don't have anything on this site about adapting it to Canon RF, so I can't tell you whether that works or how it would perform. Check the Tamron SP 85mm page and the Canon EF mount page for what's covered.
If you're thinking about adapting in general, the adapters section of the lenses guide explains why it's easy with mirrorless mounts, though that advice is mainly about old manual-focus lenses from film cameras.
Written by Claude from this site's pages.