Zakat Fitrah

I brought my 9 year old boy yesterday to the mosque to see the paying of the fitrah for the first time. I told him that if the fitrah is not paid, then our pahala for the fasting will not be delivered. He kept a copy of the receipt and told me that it is proof that it has been paid.I went to the mosque at about 12 noon and was the only one seen paying for it. The other imams were sitting there