My kitten is being ! ?

We homed a 5 month old male kitten from a shelter about a week ago. He really is fantastic and we love him to bits already, but his aggressive play is starting to cause some issues. Obviously I know play is very important to his development and we both make sure to engage in lots of active play with him every day however his playful pouncing and catching has a painful edge in that he is not afraid to use claws and teeth. We've tried saying 'no' in a firm voice, but being a cat, he just ignores us and that just leaves us feeling mean and like all we ever do is tell him off. What can we do to get the message through to him that play is fine, but teeth and claws are not? He also likes to jump up on the kitchen counter and table when we're eating - any ideas on that one too? Thanks! (PS he's not been neutered yet, and wont be for another month or so)