If it's really raining, go straight to the classroom after 9. If it's only sort of raining, take a look at the playground - if kids are out there, it's a regular drop-off.
Pickup is outside the front, rain or shine. Bring your umbrella. (Although, I have cheated, and snuck in to stand beside the front doors in the past, but that was when I had my preschooler with me and didn't want her to get too wet and cranky)
More on recess issues: http://bagleykindergarten.blogspot.com/2011/08/what-is-typical-schedule-how-much.html