This is my ANGRY face
After skipping PE, Roxas had decided that skipping school for the rest of the day was a good idea too. He was becoming a real delinquent since he started dating Axel. Skipping school, setting animals lose, going to jail, getting high, and now skipping school again. Actually, the past few weeks had been pretty misbehaved.
He'd gotten into the house with his key and had padded around the kitchen, eating anything he found that sounded slightly appetizing and the stomped off to his room with the bowl of fruit from the table and a box of granola bar.
He'd sulked in his room, alone and stuff, and had locked his door so that his mom wouldn't come barging in and bother him. He also put on some headphones and turned up the music really loud so that it blocked out all other sound.
At some point he knew his mom got home, but he was pretty sure that note on his door threatening disembowelment to anyone who bothered him was why she was staying away until dinner was ready.
As for why Sora wasn't home, making a huge racket in his room, Roxas didn't know.