When I read your post it immediately makes me wonder how much stimulation he is getting during the day when you are at work... If he is that frustrated and acting out so much for attention (good, bad or ugly), it sounds to me that he is either getting too little physical or mental activity or stimulation all day OR he is just missing you both soooo much that he is overwhelmed with wanting LOADS of attention when you are home. I know you say you give him lots, but is it constructive (not sitting a watching tv)? How is he attacking the cat while engaged in a game with you? I really think he needs more constructive one on one activity....go running around the yard in the sprinkler, ride his tricycle, go for a walk around the block in the wagon, play hide and seek, play house, Dr, pretend kitchen or dress up.... All these things can not physically be done at the same time as attacking the cat or other acting-out behaviors.
Sure, it is TOTALLY normal for him to test you, scream for no reason, etc....just be proactive, meaning to set him up for success, thinking ahead of him and guiding him in the right direction rather than waiting for him to do wrong, tell him how he's failed (and you are upset) and then struggle to come up with more and more new punishments. It's only making him more frustrated and not teaching him much other than he gets yelled at alot.
Does he communicate well with you verbally? If not alot yet, then I would strongly suggest adding a few sign language 'signs' to his vocabulary so he feels he can ask or tell you things that he isn't verbalizing yet. This can greatly lower the frustration.
Now that I'm thinking, maybe he also isn't napping well at his caretaker? Is he possibly overtired? Tired kids can't focus or listen well either, just like ones that have too much energy! Maybe consider another day caretaker - or ask how much or little excercise/stimulation he's getting and about the naps. Overall though I think he is just a normal kid. Just try to focus on the positive, and how YOU can change to make his confusing developing life easier...rather than what new punishment will work.... He's just growing up, its all a phase! Try to be tolerant and understanding of how kids are at this age.
Hang in there and best wishes!