Hi Kim,
What a stressful situation for you

I'm by no means an expert in this area, but I do have some personal experience. Your son could well be gifted, which could explain his disruptive behaviour if he is being underchallenged at school. Studies suggest that parents who think their children might be gifted are usually right (as opposed to teachers who are notoriously poor at picking out gifted children). Have you looked at some checklists for common characteristics in gifted children? There are many on the internet -this is one I like:
How Do I Know if my Child is Gifted?.
The only way to know for sure if your son is gifted is to have a psychologist perform an IQ test. If you decide to do this I suggest you find a psychologist who specialises in testing gifted children, rather than using a school councilor (who are more experienced in testing children who have low IQ scores and often will not release the whole report to you). Unfortunately a private IQ test may cost as much as $400 - $500, but it can give you a lot of information about your child's strengths and weaknesses as well as their preferred learning styles which you can then pass on to the school.
A gifted child can also be confused for a child with Aspergers or Autism (although it is possible for a child to have both). Here are some articles on the issue:
Here is a review of of the book 'Misdiagnosis And Dual Diagnoses Of Gifted Children And Adults: Adhd, Bipolar, Ocd, Asperger's, Depression, And Other Disorders'. It gives you an outline of the arguments used in the book without you having to buy and read it!
http://www.ohpsych.org/Membership/0605Review/0605Review23.pdf (book can be found at
Amazon).
Here is the original article written by James Webb (one of the author's of the above book)
Misdiagnosis and Dual Diagnoses of Gifted Children: Gifted and LD, ADHD, OCD, Oppositional Defiant Disorder and a response by one of his colleagues (also an author of the above book):
Misdiagnosis of Asperger's Disorder in gifted youth: An addendum to Mis-Diagnoses and dual diagnosis of gifted children by James Webb, Ph.D.
This article by Maureen Neihart
Gifted children with Asperger's Syndrome is written about children who are gifted and have Aspergers. She goes into some detail to discuss some of the characteristics which are common to both and how to identify children with one or the other or both.
As you can see there is a lot of research out there into this topic, and may be something your school councilor is not knowledgable about. If you are worried about your child possibly having Aspergers or Autism, then you should consult a professional (outside of the school) about it. If your child is showing some of the characteristics of a gifted child then I would assume the IQ test would still be a good idea.
Of course if your child does turn out to be gifted then you may have quite a journey ahead of yourself trying to work with the school to provide appropriately for his education. At least you will know where you stand.
Good luck with everything!
Annabel.
(P.S. I think I will move this topic to the gifted forum as other people in the same situation may find the information useful).