We've done the 9 night out of Cape Liberty a few times and as recently as this past October. We think that itinerary and departure port is a great choice and have done it on Anthem & Liberty. However, if Boston is your only option it will more than likely be on a smaller ship. Radiance or Vision class.
Agree week of Feb 12th is when it will probably open as this has been when we usually book for best pricing and cabin category location.
Best of luck and enjoy.