His father Carlos says winning the nationals was a big step up for Callum.
"This is the one that matters and everyone was laying their cards on the table for the national event," said Carlos.
"Everyone was congratulating him afterwards because it was such a consistent drive.
"The difference between Callum and the other kids was that Callum's laps were all within two and three tenths of each other from lap one to lap 20, and the other kids just fell off.
"Some of his fastest laps were in laps 18, 19 and 20. He never looked back once. He had a really good game plan which [coach] Nikki Urwin set him up mentally for and we were off."
Callum is a typical 9-year-old in that he would rather be off playing than talking - until the conversation comes round to the topic of his winning race.
He says he was not surprised he won by so much.
"No not really surprised. I have raced against them before and it has been a lot closer but we set the kart up really good.
"I love all the excitement and the close racing."
Callum has set himself some lofty goals to achieve in a few years.
"NASCAR, Formula 1 or Sprint cars - that would be good," he said.
Next step for Callum is to go to Australia and race, as he has to stay in the Cadets class for another seven months before he can move up to the Junior Restricted 100cc Yamaha class where he will be competing with boys 14 or under.
"He is at a stage where he can't learn any more and I have no doubt he can succeed at the next level up," said Carlos.