Wheel Width VS Tire Width Question

[raveer2000]

Not sure if this is where I am supposed to post this heres my question.
I am doing a 79 C10 project and I am looking for a set of wheels for the truck. We have already bought the rear tires so my question is this.
The tires are 345/40/17 Toyo Drag Radials
The recommended wheel is 12 inch wide. Range of 11.5 to 12.5
That is a tough wheel to find IMO.
I know they make a torque thrust 2 in 17X11, but the wheel we like is only made in 17X9.
What can we expect from running this tire on a 9 inch wheel?
I know it reduces contact patch from a narrower rim but there is a lot of tire there.