Ender has not been cast
Orson Scott Card posted today on Hatrack to stop a specific actor (who will remain nameless) from going around the internet claiming he has been cast as Ender:
I hear that there are rumors that a specific actor is being favored or has even been chosen to play Ender Wiggin.
If these rumors are true, then it means I am disastrously out of the loop, since we don't even have a script, the option is about to expire, and no one that I know of has even discussed casting. Who would have made this decision? I can't imagine.
Perhaps what these rumors represent is someone's wishful thinking. Rather the way Henry Kissinger once floated the rumor that someone wanted to amend the constitution to allow him, a naturalized citizen, to become President. Maybe by setting such a rumor loose, they hope it will become true.
But at this point, it most definitely is not true.