I have been coaching 9-10 YO girls for 2 years and understand what the constraints you play under. Our lcal YMCA has a program with rules similar to yours.
Defense picks up at the top of the key, man to man only.
We run pick plays left and right or High and low. The point dribbles to the side that the pick originate from and looks to pass inside to an open player. I have to make the girls shoot or else they will pass the ball off. I call one girl's name and she circles around the back side of the line and comes out low looking for a pass from the point guard who has worked herway down towards the baseline. Another play which works well for the weaker players is a multple pick play where I call one girl's name and the other girls all huddle around her, while she works her way out of the huddle and looks for the pass from the point guard who has worked her way down toward the middle of the oppisite side of the court.