If you absolutely need YouTube on iOS 9.3.5:
Alex eagerly opened the app and was thrilled to discover that it was indeed patched with the features he had been craving. He could now play videos in the background, and the pinch-to-zoom functionality was a game-changer.
In the standard Apple ecosystem, apps receive frequent updates that require newer iOS versions. Eventually, developers drop support for older hardware. For devices on iOS 9.3.5, the official YouTube app became unusable—either crashing upon launch, refusing to sign in, or displaying a message requiring an iOS update that the device cannot install. This renders a major function of the device obsolete, driving users toward modified third-party solutions.
If you’d like, I can instead:
Navigate to /var/containers/Bundle/Application/YouTube/YouTube.app/ .
While the desire to revive an old iPad is understandable, downloading and installing modified IPA files from third-party sources carries extreme risks.