Ania, Those are AMAZING scores!! particularly since he's...what 9th grade? 8th grade? That is too cool.
2 of mine are SAT testing in March (DS12 & DS10). It'll be DS10's first time. They both did well on ACT (actually, they had the same composite - 25) but I know DS10 only finished half the science test, so I think he'll do better next year. My oldest 2 increased their composites 5 points or more between 7th & 8th grades, maybe just from knowing what to expect and better time managment (I can't believe they learned that much in a year).