By "nine times cheaper," they mean the fuel for the EV can cost as little as 1/9th as much as the fuel for a gasoline / petrol car.
That's great, as far as it goes, but depreciation per mile is usually a bigger cost than fuel. Other costs like registration taxes, insurance, and maintenance shouldn't be expected to follow this 1/9th pattern either, of course. You're not going to switch to an EV and find your total expense drops to 1/9th.
It feels to me like they're telling an incomplete story on purpose.