kaboom, I have a dd who has had vision challenges due to weak eye muscles. She went through vision therapy and it made a huge difference for her. FWIW, some of what you wrote in this post matches my dd, other things in your original posts don't.
Someone at the time mentioned it might be some visual issues. So long story short we got him tested only recently he started doing funny thing with his eyes ,rubbing them constantly,he stopped reading and writing,taking 3 hours to do one math word problem( at his level) etc.
The test showed some issues for convergence the average is 12 and he got a 5 and for eye tracking he tested 2 years behind.
The symptoms you listed are things we saw happen with my dd, but her achievement testing was not as high as your ds and she struggled with visual tasks from an earlier age and consistently, whereas your ds has high achievement scores and suddenly started resisting school work.
My dd also had a very clear pattern on her WISC that related to vision - she scored consistently on most subtests but had large dips in scores on two subtests that are vision dependent: symbol search and block design. Your ds had high scores on symbol search -this subtest requires the student to find identical symbols on a random crowded field of symbols, and I think it's timed. Your ds had a lot of scatter in other subtests but it is so widespread that it would be difficult (I think) to relate it specifically to vision. Since he had across the board high achievement scores at the same age, I would tend to question whether or not he was fully engaged during the WISC testing.
I'd also recommend searching on previous vision therapy posts as Irena has suggested.
Best Wishes,
polarbear