Yes, avoid acrylic paint on your popcorn. Standard way of removing it is to thoroughly soak it with a garden sprayer and take it off with a putty knife. Should you choose to remove the texture one day, any acrylic coat you put on it will seal it against water penetration and make the removal much, much more difficult.

Be sure to thoroughly sand said spackle patches on the wall, and be sure to thoroughly clean them with TSP beforehand. But generally speaking, there should be no need to prime them.