The description of your child sounds exactly like my boy at the same age a year ago! Extrovert, weak fine motor, off the charts academics, easily overwhelmed.
I'll agree with PPs about the play-based K. My boy's private school this past year was primarily play, and it was a perfect fit for him.
We were also anxious for him about how school would handle his mix of things, but maturity has helped so much. He's no longer overwhelmed or especially anxious. His fine motor skills are dramatically better, even so much that he enjoys drawing (truely shocking). With his level of reading, he can pick up so much independently from books, and now with good writing, he's able to do math work with minimal help.
I'll agree with SAHM that 5.5 is much different from 4.5 (and so much better). My extrovert would miss school too much for homeschooling, but a good school with lots of play is a great compromise.
