I'm taking a deep breath here and saying ....maybe.
I have the same 18X8 5"bs front and back on my 68. 225/45 front 255/45 rears with the rear lowered about 1"-1 1/2" depending on who I'm parked next to. 13 1/4" from center of wheel to fender lip. Fenders well rolled,to flat. Both rear tires rub in the useual 67/68 spot. 2 o clock looking at the left fender,10 on the right with 160 lb in the back seat and a big hit(dip).
If your not sitting stock I think that extra 1/2" on that 9 1/2" wheel may cause you some trouble.
Look at it like this,on my 8" wheel I have 5" in with 3" out and at my ride hieght and tire size I cant go "out" at all.
You going 9.5 with 5.75 bs gives you 3.75" out without jacking it up or fender flares I think it will rub. The "problem" is that one spot on each side.
You can measure all this yourself it you have the car on the ground,just measure from the rim to the spring.Then ,with a strait edge,tire to rim and whatever doesn't clear a sweep of the strait edge. Then remove the tire and measure your back spacing.
It's not that hard once you look at the space.