I dont have any experience with cats mate, only dogs, but i wouldn't "wait and see" just because your suite is already fooked. He may stop on his own eventually, but later on when your out, he might think "Hmm, i might go scratch that wallpaper. Hey, atleast i wont get in trouble for it!". This is because he know's there wont be any consequences. Im not saying beat the fuck out of him everytime he does it, but a firm poke, or a spray with water and he will soon learn not to do it.

Whatever happens mate, good luck with it.