He can't help it, he's teething. This is normal puppy behavior and should be gently corrected, especially in a 8 week old. I wouldn't consider this aggression at all. He's far too young. Make sure you substitute the right chew toy for him when he chews on the wrong thing. You can try puppy kongs or any other suitable chew toy. I know it's frustrating but puppies take a lot of patience.
