There is probably an underlying reason for his behaviour. My 9 year-old took a E20 note from my purse, changed it into coins in the school canteen and threw the lot in the air in the playground!
His teacher called me at work to tell me what had happened and asked me not to give him so much money as it was causing problems at school. When I said I hadn't given it to him, she was shocked as he was a 'good kid'.
When we got home that day I asked him why he had done it and, in floods of tears, he told me that he just wanted to be really popular for 1 day! He felt his friends weren't real friends and he was sometimes left out and this was the surefire way to get back in again.
We talked about the trust issue and how valuable it is to be trusted by Mum, Dad, family and friends. His attitude has changed completely and he now takes his pocket money from my purse every week and understands that I trust him to do so and is very proud of the fact that he's a trusted family member.
I also took him to a car boot sale to help him realise the value of money and how to make money for himself by caring for his possessions in order to re-sell them at a later stage.
I hope things work out for you with your son - they probably will - this is just one of those blips in his young life that will soon be forgotten.