Two of my children were nine before the doctor finally removed their adenoids. It was a dentist who finally said, "Hey, this kid can't breathe."
Once you're recommended to a specialist, they pretty much just do it. It was more traumatic for them at this age and hard to get them to drink and they still remember to this day.
My older child had his adenoids out at three and was playing in the recovery room like nothing happened. I should have had mine out as a child but it was always delayed because of illness. As an adult, now I want them gone. It's like having a golf ball or something stuck behind my nose all the time. I have had problems my whole life with illness/snoring breathing (especially at the dentist's office), but I can't convince anyone to do it.