Unfortunately there is very little training for teachers in anything gifted, at least from what I've experienced while my children have been in school. Most think its just " smart kids who get all A's and are model students, " which in most cases couldn't be farther from the truth in a lot of ways.
Does your school have a full time gifted program? Is there one in your area you could see if he qualified for? Have you had IQ testing done as well as the achievement?
Its a hard road from what I've experienced. My son is 8 and does not like writing either. He can do it, but because he dislikes it so much ( due to the tedious nature of handwriting which he is not great at )that hes put up a wall and its torture to get him to actually do it!
See whats available in your area for services, talk to your sons school about gifted IEPs, 504s for help etc. Some schools are more willing to work with you than others. Good luck!