A pre read after you’ve already applied ED really isn’t a pre read. Most pre reads take place in summer and fall before the ED application is due. Grinnell has already started to evaluate ED applications as decisions will be released in three weeks or so.
When did you submit the preread? What sort of indication did the coach give you?
While your GPA is low for Grinnell and being test optional probably doesn’t help, your chances probably come down to how much the coach needs you on his roster and if he has any more supported slots to give. Given the lateness of your preread, I’m guessing you were not a priority recruit. But maybe I’m misinterpreting the situation and this is just how this school and coach does it. At any rate, you’ll know soon.
Good luck to you!