I think the biggest problem isn't the idea that apps created to get money through upgrades exist, but the fact that a nine-year old is given the powers of an expensive phone without the parents having a clue as to what she's doing on it is eyebrow-raising. Am I the only one bugged out when I see middle-schoolers having phones and other gadgets that are worth more than my car? Criminy, my mom wouldn't let me have a phone in my room on the main home line, never mind my OWN phone number.
And as if she didn't know she was doing wrong. Even if a child is immature in the areas of reasoning, I'm assuming any parent here would punish their kid if they found them digging into their wallet to steal cash. How is this any different? You put a LOCK on that shit, wherein any purchases made on your child's phone has to be approved by an adult first. I'm sure there's a method/service that does that. I almost never take the side of corporations like Apple, but in this case, I say the kid is grounded for six months, and double the chores in the house without an allowance. They had their fun, underhandedly. Time for parents to take responsibility for the stuff they buy their kids, especially if they don't intrinsically NEED it to begin with.