Yes you're right Laughing D. . Breast implants for minors wouldn't be performed by any doctor, (being illegal) because they're not developed enough. It doesn't make sense at all of course (he says now).
The nine year old I was talking about had plastic surgery to adjust her facial features, influenced by her idols who were fashion models.
The pre-teens may wait a few years until they're older, unless they lose interest. They've been influenced nevertheless. I know some young children have cosmetic corrective surgery, which is a necessity.
Given that medical ethics is involved
I would wager that virtually all plastic surgery performed on anyone under the age of 16 would be to correct facial deformities or to repair damage from accidents/burns. Additionally, surgery for things like deviated septa, or surgeries to correct jaw alignment or other similar surgeries to correct serious dental issues or jaw misalignments, etc. Of course, there are surgeries to correct cleft palates, and also sometimes to remove extra digits, vestigial tails, malformed ears, etc. Some of these 'cosmetic surgeries' are performed on very, very young children --even infants--in order to allow them to feed normally and to develop without delays in speech, etc.
Normally rhinoplasty is not performed until the nose is fully grown at around age 12-14. Otoplasty: pinning protruding ears back is performed on minors.
Sometimes a minor will undergo breast reduction surgery. Breasts which are too large for the person's frame can cause serious pain and back problems in addition to negative social consequences. Surgery to reduce breast tissue in cases of gynecomastia (breast development in males) is sometimes performed.
I did run across a story reported by multiple media outlets about a 9 year old Japanese girl whose mother urged her to consent to surgery on her eyelids 'to make her more beautiful' aka more western looking. In the US, anyone under 18 must have parental consent for surgery. This happened in Japan. I can't imagine this happening in the US.
Two of my children required orthodontia serious enough that surgical intervention was contemplated. The orthodontist advised waiting to see how jaws continued to grow and this proved the correct course of action. Both kids needed orthodontia but neither needed surgery.
Ethical physicians act in the best interests of the child's health, rather than parental vanity.