This is the most common source of confusion. Unchained is actually a port of Mortal Kombat: Deception (originally for PS2, Xbox, GameCube). It includes:
While MK9 never came to PSP, the handheld did receive two official Mortal Kombat titles—plus one notable port. Here’s what you can legally play on a real PSP or via emulation. Mortal Kombat 9 Psp Iso Download
If you find a file labeled "MK9 PSP ISO," it is almost always one of the following: This is the most common source of confusion