You seem to be mixing wheel and tire size there a bit
OEM
wheel is an 8.5" inch wide (not 9)...and OEM
tire is a 235 width tire.
In the rear at least 10.5"wide wheels and 285 tires fit- you can possibly go bigger, some discussion of that here-
Vendor - Model 3 Wheel Fitment by GetYourWheels
A better question might be WHY you want to go much bigger... the Model 3 doesn't appear to be traction limited in acceleration even on 8.5" wide wheels.... there's some gains to be had for other types of track use of course, but at cost of significant on-street range, and even then a square setup is generally better than a staggered one... (275s fit up front from MPPs testing)