Any idea how this will fit in terms of inner clearance?

I have 17X8 +35 Advantis with 215/45 Federal 595 RSRR. Tiny bit of rubbing at full lock and if there's passengers in rear the fenders will hit.

But generally no issues at autocross or at track days (Homestead Speedway, Sebring Raceway, PBIR)

 

we can do a little math to figure it out. The 9" wheel will be ~13mm wider on each side compared to the 8". The +45 offset vs +35 would add an additional 10mm on the inside.

Wheels themselves without taking tires into consideration will have 23mm less clearance on the inside. If you're already rubbing with the 8" +35, it's not looking good for the 9 +45.