If/when there's a vaccine, my guess is it will be handled the way polio vaccine was handled. Children in school will be vaccinated; since it's 2020 and not 1960, there will be parental permission forms, etc. - but parents who decline will find their kids suspended from the public schools.
So the vast majority of kids will be vaccinated. A large majority of adults will as well, by their regular primary care physicians.
Will there be enough refuseniks to prevent the full establishment of herd immunity - with the result that there are future epidemics? Possibly. But you know what? If herd immunity requires 80% vaccination, and we only reach 60%, because of the refuseniks... the future epidemics will only be a threat to the refuseniks. Darwin.
It's kind of like the measles situation. There are enough anti-vaxxers that we're seeing periodic outbreaks of a disease that should be gone. But by and large, the victims of those outbreaks are the anti-vaxxers (and their children, who have no independent choice, of course). Yes, I'm sympathetic to the children, who will not have asked to be left vulnerable; but I'm not prepared to be particularly sympathetic to an anti-vaxxer parent who finds him or herself suddenly losing a child to coronavirus. Choices have consequences.