No, Elon Musk wasn't necessarily the "best" student in the traditional sense of excelling in all areas.
While he was exceptionally bright, particularly in subjects that captured his interest, he wasn't always an "excellent" student, according to available information. The distinction is important. He seemed to learn at a pace exceeding the curriculum in areas he was passionate about, even teaching himself advanced concepts. This suggests that he might have been bored or unchallenged by standard coursework, leading him to not always perform at the top of his class in every subject. His brilliance was focused rather than universally applicable in the academic environment.
Therefore, characterizing him as the "best" student might be misleading, as it implies a well-rounded academic success, which doesn't fully align with the available evidence. He excelled in areas aligned with his interests and possessed extraordinary intellectual capabilities, but his academic journey was marked by focused brilliance rather than consistent top performance across all subjects.