When you arrive and do preliminary check in (the room might not be ready) you will get credentials for the extra magic hours, e.g. encoded on your magic bands. Actually I suggest going through the motions of asking, to be sure the check in CM does not overlook it.
Then you would not have to return to your resort early evening before EMH starts.
Not sure how many guests succeed in doing this, but the check in desk is open ca. 6 AM, in time to get to 8 AM morning EMHs (take out breakfast items).