9 week old puppies (basically like a human toddler) pretty much don't stop playing until they fall asleep.
7 year old dogs (generally about like a 60 year old human), don't play much at all.
This is the problem with getting a young puppy when you have an old dog. The puppy will irritate the old dog, and his nice, quiet, relaxing life has completely changed. This is why I never suggest getting a puppy when you have such an old dog.
But to answer your question, probably the only thing you can do is keep the two dogs separate, or you can interract with your puppy to keep him focused on you, instead of the other dog, all the time the old dog is around.