In that case, the store could decide to file a criminal complaint against the child.
The store doesn't have standing to file a criminal complaint against the child, it was not their card. Quite plainly they failed in their duty to ensure that the person using the card was the authorized cardholder. The contract with the credit card company is quite clear that it is the store that is liable in this case.
I think there are two issues here
The first is contractual and decides who is liable for the fraudulent charge. I agree the company accepting the card is because they failed to verify it was an authorized use.
The second is whether or not a crime was committed. Contractual liability for the loss doesn't impact that; if it did that would mean someone who stole a card and used it would not be able to be criminally prosecuted since the store would still be responsible for the loss, not the credit card company.
Of course, we are talking about a hypothetical card, using a somewhat extreme example, and many circumstances and local laws could impact what could and could not be done. However, I disagree that liability for the loss somehow absolves someone of committing a crime.