If I were you I would go with the 8.5" at the front and 9.5" in the rear. I wouldn't have a clue how much clearance there is between your wheels and your guards, but I can help you out if you can get me some information.
Your current wheel specs:
I'll need your, wheel width, offset, diameter, tyre width and profile.
Your new wheel:
Just give me your desired width for the front and back and I'll work out which offsets I'd recommend.
Also how much clearance there is between your WHEEL and your guards front and rear.
If you get me that information, I should be able to help you decide which offset to go with.