Most state's require that the student take test's to prove they are being educated. the results of these test for what would be the senior year is what you are looking for. Same paper is required for a home schooler to go to college. You should talk to the local school board.
It is not true that most states require homeschoolers take tests. I can find only 11 states that require testing. More than half the states have no testing requirements. Others have the option of testing or some form of alternative evaluation. Some require no evaluations be provided to the state at all.
What colleges want is an SAT or ACT score. Those tests are not required by states to prove students are being educated. In fact, no student is required to take them unless they seek admission to a college that demands them.
And finally, schools boards are not likely to be well informed about homeschooling requirements because they don't have to be. In most places, school boards are not involved in homeschooling at all.