Acer2428

275/35/18

or 275/40/17 is perfect for a 9" wide wheel.

Quicktime_GT

I put 285s on the back of mine with 17 x 8 roush wheels. They was hard for the tire shop to get on though, they also drove funny. You could almost feel the tire leaning left and right if you cut the wheels real quick. The was bulged out pretty bad too. Too big of a tire will also not lay down the actual tire width if you roar on it. The center will want to sling out.
I ended up buying some 17 x 10.5s. They look perfect now.
The 285 was a mastercraft, cheapest tire I could find that big. I got mine for 130 per tire.

lexy

My guy at NTB told me he can fit anything well within a reason (on 17X8) but it'll look stupid cause the outside of the tire will poke out and your inside tread will wear down slower then the outside