Here are some links I’ve found while searching for something for my 9th grade son.
I’m not sure from your post exactly what you are trying to do, so here are some sites that offer correspondence school for high school:

Here is a school that will let you turn your own studies in homeschool or music classes and life experiences into high school credit:

None of the above are free, but they’re some of the least expensive ones I’ve found.

Here’s another site that has some free high school on-line classes.

Hope this helps.

Below is the link for virtual school information in the state of Missouri:

I hope this is helpful.

I’m not sure about classes specifically in Missouri for high schoolers, but I have seen in my state a student take at least one college level class at a local college. I also took an AP class at my high school that passed for 1 semester of college. While looking up online classes for my child, I’ve seen what looked like middle and high school classes in another state. And the community college I used to attend also offered virtual and Eli classes as well. Perhaps you could find out if you can take the closest community college’s virtual and Eli classes. Maybe make an appointment with the closest community college’s guidance counselor to find out if you can apply for a few of their classes and what you should really do.
Another option is to take the classes you see that from time to time that come in the mail (snail mail) for the high school diploma or GED first and then go for other degrees from their curriculum, depending on what you want to take and do with your life. What matters, if you are going to college, is to make sure that you are taking the classes/credits that the colleges you’re trying to get into require, and maybe even expand a little bit from there to be more impressive, as well as do some extra curricular activity, volunteering, academic or exercise clubs and work to show how well rounded you are.
Another option is to call the public school you would otherwise attend and ask them about the homebound option and homeschooling options and what it would take to get the appropriate credits.
Perhaps the links below might turn up something for you.

I care!!!