A strong willed child is sometimes a difficult thing to deal with. I have one that was such as a small toddler and one that is that way as a pre-teen. I thought I'd go crazy disciplining my son at that age, seemed like all i did. However, you do need a consistent means of discipline with a strong willed child. Working full time makes consistency difficult but not impossible. I've worked full time all of my motherhood as well. Here's what i suggest
1. Set a bedtime routine, snack-story-potty-tuck in.
2. The first time he gets up. Say nothing, take him by the hand and let him back to bed.
3. You may have to do this several times and after the first time or two add "NO it's bedtime" I'm sure he'll cry but he is trying to get his way.
Same thing with the tantrums. If he hits take his hands and hold them, get down and look him in the eye and tell him no that's not polite or acceptable. You don't have to yell but you have to be very firm and each time a little firmer.
When he finds you don't give in with time. He'll begin to behave the first time. Consistentcy is the key and as a working mom, it's the hardest thing to do. good luck!!