The first game mentioned in the 'Carlsen Played' post -- 'McShane' vs. 'Magnus' -- was played in September 2004, the year Carlsen became a grandmaster at age 13. It was played at a blitz time control of three minutes per player plus an increment of one second per move. I can't imagine that anyone would play chess960 for the first time at a bullet or blitz control, so it's entirely possible that Carlsen had already played chess960 before this first recorded game.
The start position was SP317 NQRBKRBN, and after 1.e4 c6, the players reached the position shown in the top diagram. I don't really like Carlsen's first move, 1...c6. Although it opens diagonals for the Queen and Bishop, it neglects the center, allowing White to play 2.d4 with impunity, which he did.
After the following moves, 2...Nb6 3.c3 d5 4.e5 e6 5.Ng3 f6 6.f4 f5 7.Be3 Bf7 8.Rc2 Qc7 9.Nb3 Nc4 10.Bc1 Ng6, the players reached the position shown in the bottom diagram. The blocked Pawn center, which could easily arise after 1.d4 in traditional chess, looks better for White because of the space advantage. Both players now castled O-O, and White won on move 44.
After this game, ICC returns only two more Carlsen games, both played against 'JonLudvig' (probably Norwegian GM Jon Ludvig Hammer) in 2007. It's fair to say from this small sample that Carlsen was not overly impressed by chess960. Which strong players compete regularly at chess960 on ICC? The answer is on a list at Highest ICC ratings, where chess960 is the last section on the page. I'll take a closer look at this resource in a future post.