Not sure exactly how the GPA translates because of the 10 point scale – but mathematically 8.7/10 would be the equivalent of a 3.48 out of the US standard 4.0 scale. That would not usually be considered competitive for Ivy admissions. SAT score is acceptable but also unremarkable - the schools have thousands of applicants who have 4.0 GPA’s (or 10/10) and SATs of 1500 or above. Northwestern, Johns Hopkins & Rice are also highly selective. Georgia Tech is also very selective and because it is a public university, favors state residents over other applicants.
Your son sounds very accomplished and you have every right to be proud of him, but by the numbers he was not highly competitive for the schools you were targeting.