We're not in the early nineties here. The Russian leadership has changed. Putin is not Yeltsin and is much more interested in reestablishing hegemony over the former parts of the Russian empire, he is also quite a bit more ruthless, and Russian public opinion is more likely to be solidly supportive (and if not, it is in any case a lot less significant).  A second factor is Russia's economic position. In the early nineties it was quite shaky, now it is in very good shape. As a result the immediate economic impact on Russia of a short to medium term cut off of gas (say a few weeks to a few months) would be minor. In the longer term Europe would be rattled and wish to reduce its dependence on Russian fossil fuel, but considering the supply situation, that isn't that easy, and the Russians are also looking at expanding markets in Asia. On the other side the immediate impact on Ukraine would be devastating. Same goes for Poland which also has very poor relations with Russia. The impact on other European countries - the ones Russia is cultivating - would be unpleasant, but far less severe.  

All of that is a long way of saying that a Russian decision to cut off gas is both politically and economically all too possible.