My Roush 18X10 wheels with +45 offset fit at all 4 corners and clear my Brembo brakes. I have 275/40/18 up front without room for anything more. I have 305/40/18 on the rear. If the add says it doesn't fit up front, I wouldn't chance it. You can try buying the two rear wheels and checking the fitment on the front. If they fit up front, order 2 more. If they don't fit up front, order 19X8. If you're not interested in the set if they can't be 9.5 at all 5 corners, Discount tire company can order one wheel, check fitment, and return if it doesn't work.
2012 Mustang GT: Edelbrock E-Force Supercharger; Steeda UCA & LCA; BBK Long Tube Headers & x pipe; 3.73, Brembo, Roush 18X10, Nitto 555R Drag Radial 305/40/18, Magnaflow Cat Back. I am just lucky my wife let me buy and modify this car.