We used Ferber, it worked for us.
While we haven't had this problem as yet, I know he recommendt the following:
Since they don't go to sleep until 9 anyway, try putting them in bed at 9:30 for a week, with hopes that they'll be truely tired and fall right to sleep. After a week-10 days of reaffirming the 9:30 bed = sleep association, peel back the bedtime 15 minutes every night or two until you have them going to sleep shortly after whatever time you put them to bed.
In order for this to work, you must not compromise and allow them to sleep in in the morning, or steal make up sleep in the form of extra long naps.
Good luck to you and yours,
F. B.