Yeah I read the novel and the description is simply a modern cool hairstyle. So I'm guessing the mangaka with their infinitely bad taste (look at the hideous out of proportion hands) said "hold my beer"...
Dunno why people are so against the cut. My bro has a bit of a baby face, but he looks cute and attractive. His messy hair clearly wasn't better. I do agree LN had it right tho. I can only hope he grows into it over time