Okay here is the scenario:
Ender, Bean, and the rest of the group are in control of their fleet* that has just come upon a Wraith fleet** culling a human colony world. The Wraith hives spotted the incoming ships hours ago and have sent their cruisers to remove the possible threat once it came closer.
What would happen given these general parameters?
* A fleet 125 ships strong of roughly equivalent strength to those used in Ender's Game.
** 12 hives and 36 cruisers there are no darts as they are all culling the planet below.