i would use the clay bar, but only if your car needs it... if it feel rough to the touch, than clay it, if its not that bad (which i think an 09 shouldnt be) than just use the cleaner wax
my cousin is having the same problem right now, i didnt look at it yet, but it might be the slave cylinder..... or you can try bleeding the clutch pedal
i have the kdw tires... and actually was looking into getting the direzzas.. the kdw is a good tire, but from my experience noisy, and doesn't "hook" as well as i thought it would.. i think the direzzas will be my next set