The SL:9 and SL:11 are definitely different beasts. The SL:9 is not really a race ski, in that for anything above low end recreational racing, you'd probably want the SL:11. The construction is somewhat different - the base varies, and the 11 uses "power channels", whereas the 9 uses "power rods." The SL:11 is somewhat stiffer, and has a far less agressive sidecut. That said, the SL:9 is a great ski, I have the 03/04 model in a 150, I absolutely love it, it's incredible for carving up the hills - but in a course I'd definitely pick the 11.
A note about radius measurements - the stated radius is based on a calculation involving the measurements of the ski (tip, waist, tail, length). It's generally close to the size of a turn the ski would make if it were simply put on edge, no other skiier action, but it's actually just the result of a calculation. You can certainly turn a ski in a smaller radius than the number on the ski - it's just meant for comparing skis to eachother.