Are his spikey baby teeth still there? Puppy teeth are horrible and can easily hurt anyone unintentionally. His adult teeth will be much better for playing. For now I would redirect him, or spray him with water to let him know he's being too much.
Don't let the energy escalate too much until he learns how to play gently with a little dog. It's good training for him.. Poppy's favorite dogs are Chis and she nuzzles them and knows not to bowl them over like she would others.