The upgrade path is rather long (9.10 -> 10.04 -> 10.10 -> 11.04) and the
chances of it working more than once are rather slim. Since you have not
upgraded to LTS before now I suspect that risk is something you do not like.
Therefore, I would stop at 10.04. Otherwise things are bound to fail
somewhere along the path, CD or no CD. I would back up and do a fresh
installation rather than risk it if you want anything other than 10.04.