Actually, a lot of schools are deciding to take out the SAT and with Coronavirus, there's uncertainty as to when the next test date would be. That does not mean there's an excuse to not study for the SAT because there are still schools that are deciding to keep the SAT test as a requirement of admission.
Now going onto when you should start studying, it's best to start as soon as possible. I would start looking at some practice tests right now since school just started and you wouldn't be as busy. However, junior year is the hardest year of highschool and not starting earlier for studying for the SAT will just be a burden for you. It's best to start now rather than later. Also, you still have a lot of time left to take the SAT (at least 1-3 times) before your college application deadlines (most of them are usually in November/December). Although there is uncertainty as to when the next SAT test date will be, it's better to be safe than sorry. If things get better (to be honest I don't think they will), you should try to aim for taking the March SAT. If you don't do as well as you wanted that will give you until May/June/August SAT test dates to choose from. I wouldn't wait until November/December of your senior year to complete your SAT. It's too much of a risk. It's better to start studying early and taking the earliest date as possible when you are ready. If you can, you should try taking some winter bootcamp SAT prep courses (just a recommendation, you don't have to take this advice).
With that being said, I hope this helps! I know junior year is SUPER stressful and especially during these unprecedented times, I feel so bad for all juniors and seniors in high school. I wish you good luck and let me know if you have any questions! :)