I'm guessing that the reason they don't want teen fiction books aimed at ages 14+ in the classroom is because they don't want another parent coming in angry, because their child has borrowed a 14+ book from your dd, and they think the content is inappropriate for their child.
I think that, as @MaisyPops suggests, if you go in with the attitude of wanting to work with the teacher to find books that are both suitable for the classroom and that your dd will enjoy, you will get a satisfactory outcome. I also think that taking in a list of suggestions, maybe from the books suggested on here, of books that fall outside the under-10 age bracket, but that aren't the 14+ teen fiction type, would be helpful.
Has your dd tried the Bagthorpes books, by Helen Cresswell? As far as I am aware, they are for the right age group, and are very funny indeed.
A previous poster suggested The White Dragon, by Anne McCaffrey - I am not sure that is such a good idea, because it is part of a series, and doesn't make sense unless you read the rest, and the series does have some pretty adult themes in - it is written for adults.
Joan Aiken's books - Midnight is a Place, Nightbirds on Nantucket etc might be suitable. And if they are a bit outside the under 10 age range, I think the teacher would be a lot less likely to object to a classic like these books than to teen fiction.