I grew up shooting guns and started at a young age. I've let both of my daughters shoot both my .44 mag, and .45 auto when they were around this little girls age. When they shot them, I was directly behind them with my arms around them with their hands in mine to absorb and help them handle the recoil. Granted they started out on smaller caliber guns and had safety drilled into their heads.
I don't have a problem with the the age of the girl shooting, nor do I have a problem with the fact she was shooting an Uzi. The problem I have is the fact that the instructor wasn't in position to help her steady the weapon on full auto. As high a rate of fire as they have, and being noted to have a substantial muzzle rise.....I'd say yes, the instructor should posthumously be awarded the Darwin Award.
He should have at bare minimum, loaded it with no more than 5 rounds in the magazine. A full mag in an Uzi on full auto in the hands of an novice adult, much less a nine year old, is begging for bad things to happen....