The simple response to your post is YES! The S&C team is doing an amazing job with these kids.
At the very least S&C is a part of the success of this team and HCDB's system. The system requires that our kids practice at nearly double speed, getting nearly double reps, effectively practicing for the equivalent of 1.5-2X the practice of a normal team. You cannot get this many reps in without being in shape. While actual practice time is limited, how that time is used is not limited.
Also, to avoid substitutions, you have to have the strength and endurance to stay on the field. This is what beats top 25 teams in the fourth, they simply cannot hang with our guys because they are gassed.
The same conditioning allows the team to be more flexible offensively and defensively. Kids can simply do more because they are trained to do more. Having more reps in practice results in better skills and timing as well as more schemes that can be run. This aspect is especially important as the offense really is a simple offense, taking advantage of what the defense is willing to give, moving the chains and the occasional big pay to keep opposing D's honest.