Yes, of the 9 not presently underway, some will be in a training cycle, some will be getting routine maintenance and replinishment, some will be on port calls, etc. One is in long-term overhaul and is not available. Most of the others could get to sea at varying speeds, depending on how severe the emergency was. Even with long term planning for an exercise, however, I think they were only able to get 8 to sea in a 30 day window. With the upcoming loss of the Kennedy, that is something that will probably not be repeated short of total war.
I agree that a few additional carriers would be good, but subs are where there is a real shortage developing. If you got desparate, you could always use a couple of the new Amphibs as light carriers (The would be as good as anything else afloat) but there is no substitute for an attack sub.