I think he needs training. And most of what you described with biting and growling at the vet all sounds like fearful behavior. Time and lots of patience. You cant get mad and yell at fearful dogs.
And unless someone takes your dog out between your work shifts thats way too long to he alone and no excerise. Puppies need exercise. It cures a multitude of problems.
I dont know what you mean "angry" at toys. Sounds to me like he is only playing with them. Trying to burn off some energy. My yorki is very focused and crazy about stuffed toys and he Works on them till the squeaker is out and toy is shredded. I have nevr thought he seemed angry during play. |