Ender has arrived at Battle School and is receiving orientation from Dap. Dap tells them that if they break the rules and injure anyone on purpose they will get "iced-out."
"What's icing out?" asked the boy with his arm puffed up in a splint.
"Ice. Put out in the cold. Sent Earthside. Finished at Battle School."
"Nobody looked at Ender.
"So boys, if any of you are thinking of being troublemakers, at least be clever about it. Ok?"
So, according to the orientation Dap gave to the new boys at Battle School Iced means to flunk out of school.
It is my personal belief that when Ender says "I didn't leave Valentine and Mother and Father to come here just to be iced." and uses the word "iced" he means taken out. I am going solely on context and previous knowledge of the slang word "ice". In urban-speak, "ice" generally means either to be adorned in expensive jewelry like diamonds (nicknamed ice) or to be killed. Since Ender's Game was written in 1985 (short story in 1975), and "ice" was a fairly new slang term and gaining popularity at the time, that is the easiest definition to surmise.
From what I can tell, it pretty much means you get expelled.
iced, he means that he would just return and would have accomplished nothing. well not much anyways.
iced means being left out in space in the middle of nowhere