S.L.
You haven't said if you work outside the home? I assume you do since you said you need to get out the door earlier.
I'm not sure I can be a lot of help. But I'll tell you my thoughts.
Kindergartin is optional. You may not know that but it is.
It sounds to me that he needs to be in a good daycare with someone that will be able to help him mature more. If he isn't ready he shouldn't be there.
I know of some great programs that are inexpensive for him to learn on the computer. He would not need to miss out on anything and it's very doable for him to do his K year in daycare and move into 1st grade if he is matured enough by then.
Please feel free to email me privately if you want to discuss any specifics or just bounce ideas off of me. I've dealt with a great many kids that sound much like your son. I think the most important thing is to pull him out of an environment that is making him feel bad about himself and causing him to be even more clingy to you. He wants you to do things for him because he is overwhelmed and seeking comfort in being mommied.
Suzi