The question shows an image of ババラさん listening to music and waiting for マイケルさん to come back home. It shows him in a little thought bubble above her head saying "ただいま". The grammar point being focused on is the use of まで to denote "until such and such".
So my idea was something like 「マイケルさんがくるまで、うたをきいています。」 ("I'm listening to music until Michael comes back.")
But the answer in the back of the book said 「マイケルさんがかえってくるまで、レコードをきいています。」
Now I don't think the latter part is important (the difference between うた and レコード to denote what she's listening to), but I don't understand the grammar point between just saying くる for him to come home and かえってくる, which seems a bit redundant.

Can someone please help explain this to me in a way that makes sense so that I can really understand it and move forward?

おねがいします!
