Actually, depending on homeschool statutes in your state or province, and how the LEA implements them, some school districts will allow homeschool students to attend selected classes. They are listed as homeschool students, so they don't receive public school transcripts, or have to take state tests. They do have to be out of the school for some minimum amount of the time, though, so parents don't use this as a loophole just to avoid state testing. The same arrangement applies to participating in extracurriculars and sports.
You may wish to call your public school district superintendent's office, and inquire about policies for homeschool students attending certain courses and extracurriculars. You would have to comply with homeschool statutes with regard to documentation.
