If you wait until September to hold tryouts, you hear girls and parents say they are rusty because they haven't played for a month or more.
Also, with certain tournaments (Colorado Fireworks, Boulder, etc.) requiring applications to be submitted by mid-August, it is imperative to have a plan in place. Also, many teams are starting to play more fall tournaments beginning in early September.
Finally, since pretty much everything for the current season is done by early-August, why wait to have tryouts? What is gained by waiting until September?
While I agree with those who say beware of teams requiring an immediate decision, teams can't just leave offers out there for several weeks. What happens if an offer is open to a girl for a month, she turns it down, and in the meantime a half dozen other girls have gone elsewhere?
There are no good solutions that I know of, either for the teams or the players.