Should a 9-year old, without previous shooting training, be handed a fully automatic weapon? No. Should a skilled firearms instructor know better? Yes.
I believe that kids should learn about proper firearms use and shooting skills early on, no exceptions. Learning those skills – effectively – does not begin with a family vacation one-off with a fully- or even semi-automatic firearm. It begins with introduction to parts, names, concepts. It continues with sighting, trigger pull, breathing, recoil control, targeting. These are all basics that can be taught to a child with a pellet rifle, or a .22.
Progression up to larger caliber rounds and more sophisticated firearms takes time and demonstration of capability. I would no sooner hand the keys of a sports car to a 15 year old than I would an automatic handgun to a child who has no experience with any firearm whatsoever.
I have zero sympathy for the instructor. He paid the price for his reckless mistake. Unfortunately, its the child who will forever be scarred by the horrors of unintentionally killing another human being through no mistake of her own. Her parents – who had to consent to this – will owe her a debt they can never repay. She truly is the victim here.