There are a couple of possibilities here and one is play aggression. Cats do engage in rough play with each other where they really spar hard and then stop and relax and groom. They often need an outlet for that and if you don't provide them with another cat for that kind of play you may be elected to play 'whacky cat' as we call it around here. That game is much more fun I suspect when you have a layer of fur over your skin!
You have a young cat and he is probably full of energy that needs an outlet. You may be able to redirect this sort of play using toys such as a cat fishing rod type toy where the cat has to leap and grab to catch the toy you are moving around at the end of a line.
Another possbility is the cat may be now into a defensive response. If you have whacked him or tapped him he may be trying a preemptive attack before you attack him (which is how he sees it). For example I accidentally hurt one of my cats while holding the phone and talking on it (didn't see him 'distracted walker') and then suddenly he started attacking me when I was on the phone. I had to work with him to diffuse the situation as he thought that me on the phone meant he would get hurt so I changed that with positive reinforcement training.
You may find more play will help resolve this for you though.
Hope this helps you!
I've actually only had the cat about a month now. He was a stray or lost domesticated that walked into my boyfriend's house and didn't leave. Unfortunately for the kitty I live alone in a high rise apartment and I work full time. So other than my housekeeper who comes twice a week and the time I spend with him on weekends he spends most of his days alone. As such I've gotten him many toys that I play with him when I'm home and made sure some are the type he can play with on his own when alone. It just seems no matter how much I play with him it's never quite enough. I have a small covered balcony when he wants to get outside but I'm on the 18th floor so birds at that height aren't really there for him to see. In addition to the biting he middens just outside or on the edge of his litter 2-3 a week even though I scoop his box twice a day.
It definitely sounds like I'm his whacky cat partner but I'm not so sure about defensive response. He often times will bite me without provocation, for example when I used to let him into my bedroom at night (I don't anymore) he woke me 2 seperate times by jumping on me about an hour after I'd gone to bed and biting my head. He also had bitten my wrist several times, twice pretty badly. What I find interesting about it is that the last time I attempted the technique of not pulling away but of pushing towards him and it really made no difference to him. I think he would have been perfectly happy to have kept his teeth plunged into my wrist while holding on with both paws for as long as possible.
I think if you were the cat the behaviors would be way more fun!
The cat may be reacting to your eyes moving in a dream state or even snoring when he is surprising you at night.
As the cat spends so much time alone one solution would be to consider a second cat (spayed female) for him as a partner for play and entertainment. Shelters often only place kittens in pairs to cut down on this sort of problem.
They do make bird and other videos for cats too
http://www.feathersforfelines.com/
There are pet sitters who will come in and play with a pet and clean the box for you too.
With the litter box issue you may want to install a second box. Usually the number of boxes is the number of cats +1 so the cat always has a fresh box. He may be deciding not to use it because its already dirty. You might try a top entry box too
Cat Health, Behavior, Care Expert
30+ years cat owner, rescue, breeding, study of behavior & health care