So if I mean "until the battle is won" would it be okay to write "until the battle's won" or a version of that? I'm not sure if the apostrophe is being used right.
"Until the battle's won" = "Until the battle is won."
We use 's to indicate possession (Jo's cat) or as an abbreviation of "is" (Jo's sick) or "has" (Jo's been sick).
We use 's to indicate possession (Jo's cat) or as an abbreviation of "is" (Jo's sick) or "has" (Jo's been sick).