GO FOR IT! My son was responsible for himself early in the morning (he's 8 now) and my daughter is almost 4 and she is also responsible for herself (my son helps,but if he is not at home, she still takes care of herself in the mornings).
My solution for breakfast is breakfast bars. If he can't open it on his own, open it hte night before and put it in a ziplock bag. My kids can open ziplocks, but not necessarily the packaging that food comes in.
When my son was little, before I discovered breakfast bars, I would leave him a peanut butter sandwich on the counter - perfect for breakfast (in a ziplock of course).
I put juice boxes in the lowest cabinet we have and they can get to juice boxes themselves too. If your son can't open the straw yet, go ahead and open it and put it by the box. Pretty much every 4 year old can stab it into the hole by themselves.
Preset the TV if you are okay with that - put it on the channel and volume you want and then just have him push the red button to turn it on.
Life is HEAVEN when they take care of themselves for an hour in the mornings!
My daughter is only 3 and if the tv is not preset (which I do forget sometimes), she will just play with her dolls in her bedroom (she wakes up first in our house...around 5). They both (my kids) know not to come in and wake me up.
Good luck!
L.