The London-based boy, known only as Haroon, said he was being bullied at school which led to him being drawn towards extremist propaganda.
"I saw men with hands behind their backs. They were hit and told to sit down. That's when they cut their heads off. On a weekend, everyone was outside playing so I would sit freely in the living room with the computer," Haroon told BBC this week.
His outburst at school last year, when he was nine-years-old, led to him being referred to the UK government's Prevent programme, aimed at tackling radicalisation among young people in schools and colleges.
Haroon said he began looking into ISIS following the Paris terror attacks in November 2015, reading news articles and watching documentaries.
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He even played an ISIS video game.
Haroon disclosed that he was labelled a "terrorist" by classmates.
His Prevent caseworker said while Haroon was too young to pose a serious threat, he could have fallen into the hands of older ISIS sympathisers.
"We're not suggesting he could have become a terrorist but he was vulnerable and could have been taken advantage of. We're not saying he would make a bomb and blow anything up, but it's about minimising that risk," she said.