Technically no, charter schools are public schools.
If your child is enrolled in an online public charter school, you do not need to register as a homeschooler.
However many families consider themselves homeschoolers when learning at home through a public charter school.
You may participate in many homeschool programs while attending a public charter school. But your ability to participate in extra-curricular activities at your local public school will be guided by different rules than those for traditional homeschoolers.