I understand why you're looking into alternative options, but taking your son out of school is not the answer. I've been there. My teachers in grade school wanted to put me on Ritalin because they said I couldn't focus. It wasn't that I couldn't focus, it was that I didn't learn according to traditional methods, and neither does your son. Is it his fault for being wired that way, or the school system's fault for not wanting to "cater" to your son? It's nobody's fault, it's just the way it is.
Your son will need to find a way that he can study so that he'll be able to make the grades. If that means he needs to use a laptop to type notes or type papers, or even use tape recorders to tape the presentations to listen to again later, then so be it.
I was in college about to graduate before I finally "learned" the best way for me to study so that I could "make the grades". It took me 8 years to get through college, but when I go to interview or am in a discussion - nobody ever asks me how long it took to get my degree - just care that I actually have one.
Most teachers give out a syllabus that shows what they'll be going over and when. He won't like to do it, but have him actually read ahead some for the next class....It will help. He can take notes on what he reads in his computer, then "add emphasis" to those notes from the teachers presentation. Yes, it's "extra work" - but I took 15 hours over a summer - including 12 hours of intensive spanish, and got a 3.76. That's the highest GPA I received in a semester. I think it was worth it.
Your son doesn't have to be a straight-a student or on the honor roll every semester, but you know he's smart and can pass his classes. Keep him in school - sign him up with someplace like Sylvan Learning Center where they can help him find ways to work around what he's experiencing. No, you're not wanting to do the work for him, but you do want to make it easier for him - that's coddling him. He's going to need to find his place in this world, and that isn't going to help.
It isn't that I'm against home schooling - I'm all for it under the right circumstances. I know people who have done home schooling and it's turned out great. BUT they didn't do it to keep their kids from having trouble with the public school system for any learning disabilities or other like circumstances.
His success or failure in school is not just based on his teachers or specialists - yes, you do play an important role in that too in working with them and making sure he's getting the best education possible, and that they're doing what they need to be doing. Maybe he needs an individualized education plan that really addresses his needs. Maybe he just needs to work with tutors or someone at a learning center to help adapt his learning style to something that works for him.
Good job in keeping the options open and looking for input. That shows you're a great mom and want what's best for your son. You definitely deserve an "attaboy" for seeking input!!!
For what it's worth - and good luck!!