Orlando school is out the next week March 25th, and Broward schools have their first day of Spring break on the 18th, so crowds should be ok. The good news about the Saturday you are going, is the parks stay open until 10pm. They usually open 15 minutes early for busy holidays, so arrive to the gate before 08:30am, and they might open at 08:45am. You can do the major rides at what park you choose in a matter of minutes, where you would normally wait hours. For example, I've done Hulk, Spiderman, and Dr. Doom in 15 minutes. Imagine doing that at 1pm after everyone shows up. Go back to your hotel room in the afternoon and rest, then come back that night. They might even have fireworks Saturday night at 09:50pm at IOA.