2011 Mortal Kombat 9 was released so raw, that the publishers had to distribute a patch even before the discs hit the market. Without the patch, it was impossible to perform special moves or activate second player.
If you can’t make any fatalities in the game, first make sure this is really a bug and not just your hands growing out of… order. Select fatality practice from the menu and try punching some buttons. The names of the buttons should appear in the second line on the screen. If they don’t, this is a bug and you should update your game to at least version 1.01.
However, if they do, the game is OK, and you should give up everything, go to Asia, find a decent sensei and practice, practice, and practice.