No, 10's the one that had songs that homaged 2. 9 takes its menu/password theme, stage intro theme, boss beaten theme, and wily stage intro theme all directly from 2. Copy and paste.
oh, yeah, but those are only heard for a moment; though I agree they should have made new ones.
I was specifically thinking about how the intro of concrete man's theme is a clear homage to wood man's intro, for example.