Megaman 9 secret:
On the XBOX 360 version, select how to play, then find endless attack's description. The sentence "A stage that doesn't have an end" is written twice in a row.
If you deal the last hit with Hornet Chaser to the big jumper enemy, it just disappears instead of exploding.
Megaman 10 secret:
On the XBOX 360 version, select how to play, then go to the 10th page. Look at the weapon select screen. Solar Blaze is typed as S. Braze.