I just worked on this same issue yesterday. My new to me '09 had a pesky case of the squeaks. A quick cleaning/scuff didn't do much so I ended up: Removing and cleaning up the calipers, scrubbing the rotors with brake clean and a Scotch-Brite pad, scuffed pads with sandpaper and applied a thin coat of "Disc Brake Quiet" on the back of the pads. Squeak is finally gone.
wash em...