Hi Our boy is just reaching 6 months and we have been warned by our vet and our dog trainer us that this is teenager time and to expect sudden bouts of deafness and the return of naught puppy behaviour. We are following the trainers guidance that anything he does naughty wise, esp attention seeking we or he have to leave the room for 2 minutes, no longer, and he has a training line on so we can do this without talking to him or touching him. Cat bothering is one of those sins as is jumping on visitors. He knows the command off which covers a lot of things so its Off if he's heading at the cat or jumping on a visitor or barking at them and if he carries on, goes in another room, if he does it again, the same. He does seem to be learning to leave her alone. The other cat spits and growls so he's a bit less keen on getting close to her. To be honest when we have visitors he often has to go in a pen until he's calmed down - sometimes about 30 mins
Good luck.