I assumed it would be a low end board, why? because no-one will stick a 8600K in a high end board, chances of it being z370 was highly likely over z390, and a cheap one at that if budget would get a 8600k.
Just google it, its all over the net, most people will stick a fan on their VRMs because they are not designed for the power the 9900k wants, especially on cheaper boards, maybe just don’t overclock 
9900k is a superb CPU though, i would say monitor your VRM temps, but cheap boards don’t have the sensors, so would have to use an external thermometer.