The hope that these guys are going to grow always makes me laugh. It's weird how they seem to be younger every year, I know, but 18 year old's are generally done growing upwards outside of extreme cases.I found this link on the correlation between foot size and teens' height: Normal Height & Weight for Boys | Livestrong.com. You can "estimate a teen's height in inches by doubling his shoe size and adding 50". So 12.5*x +50 = 75. That would be 6'3"! He probably won't grow to that height but packing muscles in a 6 feet body frame with his tenacious style should make him a good fit with our fancy stars.
In short, both his body and his play have been in an upward trajectory. And usually it is better to pick someone on the upward swing than someone plateauing.
And that shoe size thing is going to be like a 20% correlation at best. He'll put on plenty of weight as he matures into his adult body, and every NHL player grows an inch when they get put on NHL.com, but that's all that's likely.