Never been in September, but we were there May 14-19 and loved it! Crowds were low, not sure if it was the timing or the rain. It rained for hours every day, but we didn’t let that stop us. Rain jackets and Keens saved the day, every day. On Monday we were able to get several fastpasses at MK, we hoped from AK to MK at 6pm and were able to get fastpasses as soon as we tapped our magic bands for 5-10 minutes later.