I have a hard time not wanting to bet there. There are very few kings in his range that just call there assuming he's a semi decent player.
Without stats, I can only say that KQ, 88, TT a9 and perhaps a really passively played K9 make sense.
The Dunning–Kruger effect is a cognitive bias in which unskilled individuals suffer from illusory superiority, mistakenly rating their ability much higher than average. This bias is attributed to a metacognitive inability of the unskilled to recognize their mistakes