Perhaps you did not bother to read the comments thus far before opening your proverbial mouth. Allow me to rectify your willful ignorance.
First, nobody ever said it was the girl's phone. Perhaps Dad handed her his phone and said "Yes, you can play your game for a few minutes."
More to the point though, these games are often very subtle about how they get you to pay and buying something on a smartphone is the simplest process in the world. You hit a button, your card is instantly charged. And while the wording of a "buy premium stuff now" pop up might ring alarm bells with us mature folks - and even we miss it often enough - who can fairly blame a 9 year old for missing something designed to fly under the radar of most adults?
While I do not disagree with what you are saying, I would suggest having all of the facts before condemning specific people.