I think it is worth pursuing with a professional that is very experienced withe ADHD and learning. I agree with DeeDee that a developmental pediatrician would be appropriate. You might also consider a neurologist that specializes in learning and ADHD or a Psychiatrist. These medical doctors will most likely recommend a full neuropsychological evaluation that includes cognitive testing and achievement testing by a neuorpsychologist that specializes in educational issues.

As far as the OT - there could be some interplay between the two. If he does have ADHD-inattentive type, this is often a situation where he has difficulty regulating and weeding out sensory input. It really isn't "inattention" but scattered attention to everything around him. OT's can offer instruction in certain self-regulation strategies that may help him zero in and focus on only the things that are important. You can will also learn if his handwriting difficulties could be supported by occupational therapy.

I worry about your pediatrician's comment that your son could be a "divergent thinker who needs to turn on the consequence side of his brain and learn to concentrate." ADHD is a medical condition that involves the dopamine levels in the brain. Because the levels are slightly out of alignment in the brains of those with ADHD, there is a medical reason for the inattention. You would no more tell a diabetic that they need to turn on the consequence section of their pancreas and expect the insulin levels to be appropriate. But, like diabetes, for some people there are strategies such as exercise that can help regulate the problem. For others, they need both the strategies and the medication.

I think you should follow up and get more information. It could be ADHD it could be something else. But, the only way to find out is to evaluate and speak with experts.

Best of luck.