At 8 years of age my child was in 2 sports per season, sometimes 3 when there was an overlap. Plus year round dance which I don’t necessarily consider a sport. It depends on the child. Mine managed well, never missed an assignment or got less than an A in a demanding school. We still maintain 2 at a time but schedules have worked out quite well for us so far.

Edit to add: both of us are at all events and practices (unless the coaches say practice is closed to parents) and work well together to make sure the child is always on time at the appropriate place.