Use iTunes 12.1.3.6. This is the final release for XP and includes support for iOS 9 devices.
Compatibility depends heavily on which Service Pack (SP) your Windows XP system is running: itunes download for windows xp old version
While less common, the iTunes 12.1.2 64-bit installer is typically the last version compatible with this architecture. Where to Download Legacy iTunes Use iTunes 12
Use iTunes 11.1.5 . This version is the most stable for SP2 systems and avoids common installation errors like "Data Execution Prevention" (DEP) crashes. Where to Download Legacy iTunes Use iTunes 11
The latest and final compatible version of iTunes for Windows XP (Service Pack 3) is . While Apple ended support for Windows XP in 2015 with the release of iTunes 12.2, users of older hardware can still download and use specific legacy versions to manage their music libraries and sync older devices. Choosing the Right Version for Your Service Pack
Since Apple no longer features these versions on its main download page, you must use direct support links or trusted archives: iTunes on Windows xp - Apple Communities