You could explain why it matters, instead of complaining that people don't understand. Delta-8 is also psychoactive and not well known so it's easy to mix up.

CBD has been legal for a while and is completely different than THC products so it shouldn't be compared.

Stating Delta-9 is legal, not Delta-8, is not that big of a difference. If you think it is, you should talk about why it matters because your attitude obviously hasn't worked thus far for dealing with people who just don't understand. Maybe, you're not concerned with people understanding as much as you state.