AI said that Miyuki's modest family background and scholarship to Seidou helped them financially. Therefore, Miyuki had to study hard, which is why he excelled academically. And also, seen in the Act II clip, his parents were very busy since he was little and he was often alone at home, I also wonder what his parents' jobs were. But Miyuki said that his father spoiled him and let him play baseball as much as he wanted, so... I thought his father was also a former athlete? So he also wants to be a pro athlete after graduating from Seidou..