New ENL co-teacher (HS)

I will begin my first year teaching this September, and I've been hired to be a co-teacher in an ELA class, most likely 9th grade. Not only do I not meet my co-teacher until a week before class starts, but I'm told I won't know how many ELLs I have until the first day (or second week tbh).

What can I do now with the time I have in the next couple weeks to prepare? Any advice helps. The only thing I can think of is to study standards and look at example curricula, and plan some assessments I may or may not use. I feel like I can't really start until I meet my co-teacher, see the room, etc.