I guess because I forgot I ever posted this and someone might stumble upon it with a similar situation, I should provide some updates.
1) Son was tentatively diagnosed ADHD at 4, definitively at 6, and has been on a non-stimulant Rx for impulse control specifically since that time. We've experimented with stimulants but have never been able to find the right one at the right dosage. (They all destroy his sleep which is already a delicate matter since infancy.)
2) Son was later determined to have sensory processing challenges, but not autism, after an evaluation at age 9.
3) Son tested into his school's gifted program at age 8. He was recently retested at the school's request and his scores on the CogAT were 152 Composite (132 Verbal, 148 Quant, 151 NV). His TerraNova scores were much less impressive and we're currently trying to understand the source of the gap between aptitude and achievement.
4) Still wants to be an astronomer after 8 years, but also now an aerospace engineer so he can use his knowledge of astronomy to better design spacecraft and technology suited for deep space exploration.
