How do I make sure our pit bull has a good temperament?

My family and I have just been given a male pit bull puppy. He is eight weeks are SOOOO cute! I've always wanted a pit bull but when my Aunt and Uncle kinda forced him on us (Auntie HATES dogs) my mother was pretty skeptical... We have always raised loving, fun, gentle dogs. This puppy,i've noticed, has a little bit of a temperament problem. He growls at our year old dog Sadie when she gets close to their bed...Or close to their food and when their playing bites her pretty hard so she runs away. I know he is just a puppy but all of the other dogs we've had before never were that temper mental. We don't want him growing up to be an aggressive dog. Any suggestions?