He's a little on the scrawny side, maybe, but I have two adult males who have been scrawny their whole lives (they're 5.5 years old now and we've had them since they were babies). Compared to my other cresteds, especially some of the females, they look super thin, but they seem to be thriving despite that. If he's holding steady at that weight and not fluctuating up and down or losing weight suddenly I probably wouldn't worry too much about it.
He looks okay to me--spine, hips and ribs are not protruding at all. Males can be smaller and thinner than females, especially when young. Feed him Pangea Fruit Mix with Insects--that has plumped up all of my geckos.