First you need a diagnosis from a doctor/neurologist to support your claim. Second, request the meeting with the school officials and have that information on hand, let them know that you will go to district and raise hell if your child doesn’t get reasonable accommodations through an IEP (he can have both gifted classes and ADHD accomodations). By law the school districts have to work with you. If you are a single mom and your child may have Medicaid (not making an assumption just throwing this out there for other parents in similar situations) then the Federal Govt. is paying a Federal share for these services and I don’t see why the school wouldn’t want to work with you, the school even gets a Federal Share to cover admin costs.
I have to go on a vacation shortly but please update post if you don’t get nowhere and I will get all the Federal criteria related to IEPs, your child is entitled to a reasonable accommodation because of his ADHD and intelligence is not a factor nor a criteria to get it. My son has a high IQ in the 3rd std deviation (fluid reasoning) yet he needs reasonable accommodation due to his ADHD in order to succeed and get good grades.