I'm appalled at the response you've gotten from the school, as I'm sure you are. Have you filed a complaint against the principal with the district? The principal is responsible for enforcing safety standards in school, and his behaviour belies a troubling disregard for his duty of care to the students under his watch. Death threats are no trivial matter, and there should be a serious disciplinary intervention to address the problem behaviours so that the issue is never repeated, either with your child or others.
It's wonderful that you have the ability to homeschool and remove your son from such a negative environment, and I applaud you for taking that step. Your son will benefit.
As to homeschooling, it will involve significant time with your child, and you'll need to honestly self-assess to determine whether it's a fit for your family. I don't recall your son's age exactly, but as both a former SAH homeschooler and a single parent who homeschooled part-time while teleworking, I can suggest the following broad strokes of what worked for us:
1. Set up a dedicated work space for your child to work in uninterrupted. All work is done in that space to clearly separate work and leisure areas in the house.
2. Plan out a consistent daily schedule for your child, and provide clear instructions and demonstrations of the work expected. This will empower your son to focus and provide an effective effort in the allotted class time. You might be in the room or general vicinity in the house doing an independent activity at that time. School work will probably occupy at least 3 hours a day and, with good work habits, that will give you a substantial envelope of solo time each day.
3. Depending on how your own schedule is formatted, plan to incorporate some physical activity regularly throughout the day to promote focus and enjoyment. This might look like the two of you going for a bike ride for an hour before your start time; taking an extra-long lunch break to shoot some hoops together/kick around a ball/go for a run together; or attending a martial arts or yoga class together after school. Getting in this time will cover multiple bases--you'll both get exercise and practice in sports, you'll burn off steam and, most importantly, you'll have a great time together.
4. Arrange a set time (say, half an hour) every school day for your son to "present" independent research results to you. This is a great opportunity for him to synthesize his results, prepare a storyboard, practice public speaking, and get the attention and validation he needs and craves. It validates his efforts, gives him an opportunity to access feedback, is terrific practice in presenting, it acts as a springboard to great discussions to extend content, and gives him an incentive to get his work done (because having a poor presentation is embarrassing).
As to scheduling in alone time, I think you're going to have to do a personal inventory of your son's needs and yours and honestly evaluate where each of you will have to bend. You don't mention whether your need for alone time is motivated by personal preference or a need to balance telework with your son's homeschooling; that context would be helpful for me in terms of providing feedback in that area.
