Parent asking why their child is never goalkeeper

I would not force a child into goal simply to prove everybody has had the same experience. There is value in children understanding the position, and I would offer them chances in training where the pressure is low. But if this U9 has no interest and is happily developing outfield, I would not make matchday goalkeeping a compulsory rite of passage. The important thing is that the family understands the decision is not because the child “isn’t good enough” to go in goal. It is simply about responding to the player in front of you. You can say that everyone gets opportunities to experience different parts of football, but those opportunities do not have to be identical. If the child later becomes curious about goalkeeping, give them the chance. The door stays open without pushing them through it.