Regardless of where you get them or even what brand/model/style, even if you can get a 9" wheel/tire combination up into the wheelhouse of your particular A body without rubbing (don't forget they need to go as high into the wheelhouse as they would be at full jounce), these with almost seven inches from the mounting surface to the inside of the wheel, will quite likely have major clearance issues bolting on to a stock A body axle setup, requiring the use of quite thick spacers.
Determining allowable wheel size, backing spacing, and clearance with the axle in place at ride height is pretty simple if you make a male cardboard or plywood template of the desired tire outline/wheel mounting surface combination, take off the rear wheels, and support the rear of the car on jackstands. While this can be done on the garage floor, I, for my not so young anymore comfort, will prefer to borrow a friend's four post hoist. Setting a framing square against the brake drum and on the ground plane allows you to slide the template against it up into the wheelwell to measure the jounce clearance with reasonable accuracy. Most tedious and time consuming part of the whole operation would be making accurate template(s).
I plan on using the 6.2" backspace, 17" X 8", '06 Mustang wheels/40 series tires my little sister gave me (as in free). I figure my 3.55 Suregrip slipped in a stock width 68 to 70 B body axle and the Duster's rear fenders will get me close. I'll turn hubcentric spacers to fine tune if needed, or turn down the axle hubs to fit the wheels if not.
they will fit our cars with a 3/8" spacer 
