I think all schools of certainly junior upwards would have an unofficial hierachy.
Generally the loud confident (I wouldn't include bright in this particularly, they may be in here, but just as likely in other groups) possible sporty are at the top. What we always referred to as the "in crowd". Often very cliquey, doing a lot outside school together. Often the group that pushes boundries as well. And the group that's often most likely to have a huge row and split off into rival factions.
Then the quietly confident. More often paired off into smaller friendship groups. I would say they're quite often the ones picked by teachers. Often the ones who enthusiastically join clubs etc.
Then the ones who keep under the radar. They may be shy, not particularly good or bad at anything. They are usually in small friendship groups. Don't particularly choose to join in with things.
Lastly the loners. May be very bright, or really struggling academically. May have some reason why they don't appeal to their peers. May be bullied. May be just left alone. May be miserable at not being in a freindship group, or may really not care. May sometimes tag along with another group, but not generally the in crowd. May really be in this group simply because they don't fit in with any of the others. Or may be desperately trying to join a group but being constantly rebuffed.
Vast generalisation here. But in my experience it is unusual for much movements between groups once the groups have settled, although friendships inside groups may alter.
You could learn a certain amount from the head's reaction to repeating what the lad said to you. Make sure you say that you specifically asked him to say one thing to change about the school (really good question btw) and see what he says.