Israel sounds like it is on the verge of entirely shutting down due to coronavirus fears, so I think I will have to abandon my plans to visit in a week and a half and continue from Jordan to Malta instead. Even if I can get in, it sounds like I might not be able to get out again without undergoing quarantine, which does not sound particularly fun.
Hopefully there will be availability for the hypogeum due to decreased tourism, at least...!
I think you should be safe, even without coronavirus. I managed to get a tocket for the hypogeum two years ago in August by going to the National War Museum on a Sunday morning to buy tickets for the next day. Even if it was 9am, there were still tickets, even though I had read messages you should go earlier if you want tickets for the hypogeum. Seems in Sunday morning people are later, somehow? Or maybe I was just lucky?
But anyway, it should be possible to get tickets for the hypogeum for the day after.