It is okay for your 8 year old son to use a pacifier.
I used a pacifier when I was 8 years old and still do.
I also saw a boy about 7 who was using a pacifier in Walmart a few days ago and he didn't seem embarrassed at all.
I smiled and wished that I could use my pacifier in public without covering it up.
I have although sucked on a pacifier in public when wearing a face mask and when I needed to talk I would just drop it out of my mouth into the mask.
I also suck on a pacifier at home and out in my yard.
There's no age limit for pacifiers and if your 8 year old son wants to use a pacifier then he should.
Also he should wear diapers and drink from bottles as well.