The most famous and stable PSP ISO versions are fan-made remasters of Inazuma Eleven 2: Blizzard/Firestorm and Inazuma Eleven 3: Team Ogre Attacks . These are the titles people typically search for when using the keyword.
If you have found a community-made Inazuma Eleven project, you typically need a PSP with custom firmware (CFW) to run it. Format the Memory Card: Game Inazuma Eleven Psp Iso