Before I bought the 08 390's, I tried on a pair of S/M 07 390's with the straps and all fully extended. I wear a size 9 boot, and the bindings didn't fit them too well. Tried on the 08 L/XL and the fit was solid out of the box. Technically the S/M 390's can fit a 9.5 boot, but it won't fit too well, if the 07's I tried on are any indication of how they'll fit you. Personally, I'd nab the L/XL's.
Also depends on your boot IMO. Salomon F22's have a smaller than average footprint.