Opinion: U9 Soccer Positions

Not being a soccer player myself, I'd like to get the opinion of those
that play/have played.

I have a daughter in U9 (competitive, as opposed to recreational)
soccer. Her coach appears to have, from the very first game, decided
that each girl will play one position, and one position only. U9 is
7v7. Her coach is setting them up in a 3-3 formation, 3 forwards and
3 defense. No mid-field.

Up til now (she's played for 5 years) my daughter has been a
phenomenal forward with a pretty decent scoring touch (typically 2-3
goals/game - proof is in the pudding, not me being a proud poppa!).
Her coach this year decided to place her (and keep her) in the central
defender position of the 3-3 formation.

My own personal opinion is that U9 is far too early to pigeon-hole a
developing soccer player into any one position, save perhaps the
keeper. While I believe it is good for her development to play
defense occasionally, she is absolutely miserable in that position and
tends to move forward.

What, if anything, should I say to the coach? I merely want my
daughter to really enjoy the game. She doesn't mind playing defense
occasionally, but her passion is as a forward. Having said that, the
coach no doubt doesn't mind having a strong player, who can control
the ball without kicking it away every time she gets possession, on