I have a dog with 3 cats.
We didn't get our cats until the dog was much older so we didn't have to deal with an excitable 8 month old pup. Hissy's ideas are excellent. My dog knows what gentle means so that went a long way for us. The fact that you have said it is getting better is good. Your dog is young and I'm sure very smart. These things just sometimes take time so I would be patient. Definitely keep the dog under control. Offer rewards to your dog for good behavior with your kitty but never with rough behavior. When we got our first cat everytime they were gentle, came close and were calm, etc...we would give the dog praise and pets. It was an exciting day when they sniffed noses. Really praise your dog when he's gentle. The other advice I would offer is to make sure your dog feels special. The more he feels left out the harder it is. Dogs don't want to miss out on anything. I don't think the control issue will totally go away ( my dog controls by stealing the cats toys
), dogs like to be alpha but your dog and cat are young enough I would bet they can be great friends! Oh, and more thing. As you probably know, dogs are very food oriented so I would feed them at the same time....my dog looks forward to a small kitty treat too when I feed the cats. Make sure that the cat has safe places to go too. And even if they aren't buddies I will bet that they will work things out. I'm no expert but these were our experiences. Good luck!!!!
PS Have you had turd eating issues yet? That is a defintie reality with cats and dogs living together.
Dogs love kitty poo! Keep us posted!