As I understand it, C9 and C13 are extended dominant seventh chords (with an added 9 and an added 9, 11 and 13 respectively) and would not quite fit over a Cmaj7 chord (though that's mainly the seventh's fault). Well, depends on what you want in your sound...Well, yes, but then wouldn't you favor C6 arpeggio or C9 or even C13 over Cmaj7?
maj7 chords.