Baffled how people can defend Disney in this whole thing... If your entire communications strategy to guests is that everyone will have a fair chance with boarding groups at 8am, that's when you enable the system. Not secretly before, so that those who planned their entire morning around being in the park by 8am are left out for the day. Imagine you're a parent on the last day of their trip whose kid loves Star Wars - you do everything Disney has asked you to do, only to find out they lied to you about what time to be there. It's wholly unfair. The park is not at capacity at 8, regardless of what time they actually opened, there's plenty of room to let everyone in (including EMH guests) who have arrived before 8am, giving everyone a fair shake at the boarding group process.
Simply open the park at the specified EMH time and give out wristbands to those eligible so the attractions CMs can know who can ride. Whenever the park duty manager decides the crowds out front are too great, they can start letting day guests in, but those without wristbands can enjoy the park, have a coffee but not take advantage of the EMH attraction access. Then everyone, regardless of their resort status, gets a fair chance at boarding groups. This is not rocket science.