Yes, Russian banks can save the ruble, because Russia is a lot more modern than it used to be. Russia is no longer cut off from the rest of the world. Russia can look at what worked and what didn't work in the financial crises in Europe, and they can make good decisions based on that.
It really depends on the response from the country. It could be saved depending on the actions of everyone that is involved, the politicians, the people who live in the country. They may need to completely redo their budget system and it might take several year to fix the financial crisis.
The banks didn't anticipate such a drop in the ruble, but they should have had a back up plan to save the ruble if it did. They chose this action and a sensible decision would to be do it only with a strategy that would save them if it backfired.
Up until OPEC allowed the price of oil to free fall to unprecedented levels, the Central Russian Bank was actually doing a pretty good job of managing what appeared to be an impending financial crisis. It first allowed the price of the ruble to fall also, thus leveling it out with the price of oil. But once the price of oil dropped below $65 a barrel, there was really nothing else for the Central Russian Bank to do, including now.