Seems that there are a couple of things that are pretty obvious.
1> The stud colt has only learned how not to behave which means that he is smart and knows how to get what he wants.
2> He has decided to excalate his behaviour to the point of being unsafe to get what he wants.
3> He is full of energy--probably need to take a look at what he is being fed--and for sure confining him in a stall is definitely compounding the problem.
There is only one answer--proper training which includes proper diet, proper turn out etc. For sure the OP can't provide the total package. There is no other advice--get the colt to someone who can solve the problems.
Gelding him will not "fix" him--it will help but it is not the majic answer--nor is turn out, nor is diet. Its a combo pack and without the correct combination of all of the above he will only escalate his behaviour to become an extremely dangerous animal period.
Please be very careful--he can, and will, hurt you. Get some help as quick as you can. If you can't afford the help--sell him.
Lots of great advice, thank you to all who have contributed. He is outside today, running and loving being in pasture, with a raised voltage fence that has a new, higher strand that he can't jump. I'm calling the vet this afternoon to set up gelding.
As for feed, he gets 6 flakes of hay for a 24 hour period. Plus at night he gets two cups total of- hay stretcher 70%, oats 25%, and corn 5%. I don't feed any sweet feed or molasasas products.
I have made a point to not back up from him, and have actually been getting him to stop and think about it when I make him back up, so I have a renewed confidence that this will work, after alot of hard work on my part, and good advice. My vet happens to be a trainer as well, so he's going to help me work.
Thanks again everyone!
Everyone is basically right. I have a 5 year old that started acting the same way as soon as I started boarding her inside for training. Because you don't have turnout for him I would reccomend not giving him grain or a low energy grain. Plus if you have the space and you only need alittle lunge him until he can't anymore. Get that energy out as best as you can and that