Sept 15 is the deadline for EA Round 1. Accepted students don’t have to commit until May 1. Merit doesn’t start coming out until November, but on this year’s Auburn thread it doesn’t look like merit started being released until Dec.
It’s not really auto merit, the numbers are estimated and not guaranteed (see link), and can change year to year. I haven’t seen good data, but the website says those who apply early have best chance at merit.