Genie in a Bottle by Sarah Mlynowski
Whatever After continues.
In their world, there is a competition for donations to the school library via a readathon.
Abby, feeling frustrated that she can't win and name which books are to be bought, goes with Jonah, and of course Prince, into a dusty road where children are playing a game with a ball. And one of them is Aladdin.
Only Jonah gives him a bloody nose, so he's not there when the evil magician shows up. Abby and Jonah decide to take his place and fix it. (Fortunately, Abby knows the original tale.)
It involves jewel fruit, the two genies of the original tale, discoveries about freeing Maryrose, a squirrel, the princess's love of flowers, and more.