Sexual maturity

Hi every one, I was directed here by someone at parrotforum to seek any further advice you may have about my B/F Amazon...so I'll repost what I asked on that site. Every suggestion helps!

I have a 5 year old yellow crowned Amazon who has been an absolute nightmare since around this month. He started off by jumping off of his playgym and dinner stand to try to rip me open with his beak anytime I would walk by. Then he progressed to screaming incessantly anytime,and I am not really sure what to do to change this behavior. I see agression when he plays with toys and bite me more seriously and sometime coming, biting and going back to the cage.
I've bought him 2 months ago and seller said he is 4 y.old so know seems 5and I cant say he's been such a great bird until now but until thise days he played very good with me without attacking me and bited less and less.He learned to step up...it was very nice to see:19:

Unfortunately, if this behavior continues and I cannot correct it, I will have to find Jacob a new home, which I really don't want to do. Sorry for such a long post, hopefully you all can help me out. Thank you!

Has this bird been to an avian vet?
What diet is this bird on?
Does this bird get 12 hours of uninterrupted sleep?
Does this bird have toys?
Does this bird have a seperate play gym to hang out on other then his cage?