For white male teens more into fashion and all around swag, usually going for high and tight hair. Sides not quite bald, super duper styled top, lot of volume at the top, and an optional cut-in part on either side where the fade meets the top. To be honest lots of guys, regardless of race, are into the basic skeleton of this cut in one way or another. It's been pretty popular for about 5 or 7 years now.
If I had to pick for Conner, I'd say go for the high and tight, leave a lot of hair on top to work with, but too far, and maybe imply that he has some natural curls to him--nothing too crazy, but enough for you to visually get it. Should probably look very deliberately styled in contrast to Clark's who only styles just enough as Clark, but lets it do its thing as Superman, and Jon who probably couldn't give a damn about his hair right now. Regardless of what personal growth Conner has gone through, it shouldn't be lost that he has flash to him and he has narcissistic tendencies that--regardless of genetics--separate him from his older "brother."
Cameron Stewart does a pretty slick and subtle update. The gauge earrings are a super slick touch, and I hope DC takes them into consideration when reintroducing Conner. The aviators are an obvious must.