We don't home school someone who does might be able to answer this better than I. With that being said you kind of have to prove some kind of schooling to the state. Autism is not exempt from education. As dumb as it may sound my nonverbal severe child who is 11 with the cognitive ability of a 2/12 year old still has to be formally tested in standardized testing. The standards are different than an NT child but they still have them.

I live in Las Vegas I have a 11 year old autistic daughter. Who I do home school. It's against the law here for an child here not to be registered in school of some type. We send a letter to the school district with her education plan that's it I write a letter explaining her situation they send you a letter back. That letter proves you are providing education for your child that's all that is required for most states. You just look up your local school district website it will have either the address to drop off the paperwork, a email or mailing address only. It will tell you paperwork like form to fill out and what is needed. Then look up your state requirements for your homes schooling education plan. if there is something on the list the child is unable to do just explain as to why the child can not and what your doing to replace it or if the child is to young mentally that's exc. Send in your education plan with the home school form. You will receive a letter in the mail or email saying yes or what else needs to be done. Due to COVID-19 a lot have states have changed the regulations for homeschooling offer more free programs free tools.

To the best of my knowledge, there is no state in the United States where any student can be denied an education until they are at least 16 years old, regardless of whether or not they're Autistic. They don't have to be enrolled in public school, but if they're not attending public school they need to be receiving an education elsewhere (ie: private school, home school, etc). In some states the age at which students can legally stop receiving an education is higher, but not in Florida.

In Florida, all children between the ages of 6 and 16 must attend some form of school. Students who accumulate 15 or more absences in a three month period without the knowledge of their parents or guardians are considered habitual truants, and can face legal repercussions for their actions. I can't find any law in your state that requires Autistic children to attend school longer than non-Autistic students, although I'm not a lawyer or an expert on Florida's laws, so I can't guarantee that no such law exists (it would be a very odd law if it did exist, though).

If your question was about why Autistics aren't exempt from truancy law, the answer is that being Autistic doesn't render an individual incapable of learning, so it would be wrong for the laws not to ensure that we receive the same amount of formal education as our non-Autistic peers.