Homeschool moms PLEASE HELP?

I have two 14 yr olds. both are in 8th grade and attend public school. I need to know how I can to find thier true levels in all subjects. I am concerned with the scores the school is giving me and I am not sure how correct they are. As Homeschoolers how do you test grade levels? And is there a summer program that you use that may help me to "catch" them up? Please help me anyway that you can I am concerned about the many issues I am seeing and don't know where to turn.