havesomeseichel: I just found out the exact details at my sons’ Yeshiva, and I assume it is similar for other Yeshivas. Boys in 7th and 8th grade are required to be there for minyan at 7:30. They then have breakfast and begin learning bet. 8:45 and 9:00. I do not have HS kids yet, but I am assuming that their schedule is similar. Younger kids are allowed to travel on school bus transportation provided by the city, for them it is not an issue.
If the Yeshivos would start at 8 or 8:30 that would be the same time as the PS, 8:15 – 8:30. The Yeshivos are different. The point is they do, in general, travel at separate times than the PS kids. Also, PS kids get out at 2:30 – 3:00, so traveling home is NOT in conflict with PS dismissal for the boys or girls.