33's will fit without a lift.
Properly backspaced wheels will help, as JohnHoss stated.
Going to 33's will gain only 1/2" clearance.
If you want to increase tire size, might as well make the jump to 35's. Just save up for a modest 2.5" lift and you'll be happy based on your driving conditions. Even a Budget Boost (~$200) will work in your case.
2008 2-dr Rubicon, auto,
RK 2.5" Max Travel lift, Fox 2.0 shocks, 37" Nittos, 5.38 gears, River Raider skids, Warn VR8000-S.
RIPP Gen 2 Stg 2 Supercharger.
Bunch of other junk.