I don't really think this changes anything.
Given that the vaccine seems to turn the delta variant from a potentially serious, sometimes fatal disease, to a mild annoyance, I would think that plans could proceed as normal.
At a certain point, when Covid ( delta variant or not) becomes less dangerous than the Flu or Rhinovirus, it may not make sense to worry about.
In the UK schools have been fully open since Feb, except that bubble in schools have to isolate for 10 days if they have close contact with someone with the virus, which is pretty frustrating. This is expected to change again in August to be less restrictive, ready for school opening in September.
Starting dates vary, but generally schools will start their new school year in early September. That's when we'll really see what happens. But I'd expect most school districts to be doing full time in-person learning based on US CDC recommendations; many districts will likely make an optional online program available, but I doubt there will be many districts doing widespread online only or hybrids like we saw in the 2020-2021 school year.
I also would imagine it’s highly like the 20% of teachers not vaccinated probably had covid already…( just my guess)
1. https://www.hopkinsmedicine.org/health/conditions-and-diseas...
2. https://www.cdc.gov/media/releases/2021/s0406-teachers-staff...
My new employer is already back in the office as of June. According to the hiring manager though, at least 95% of the employees have been vaccinated, but those that haven't are also being subjected to the twice-a-week mandatory testing.