Elias wasn’t trying to reinvent the wheel. He just wanted to watch a woodworking tutorial in his garage without having to prop up his iPhone. But when he tapped the YouTube icon, the app gasped, flashed a "Connect to iTunes" prompt, and died. Google had killed the legacy API months ago. The App Store, usually a vibrant marketplace, looked like a ghost town for this device; every "Update" button was greyed out, demanding an iOS version the old chip couldn't handle.
I understand you're looking for a YouTube IPA file compatible with iOS 9.3.5. Let me give you the detailed story — including why this is difficult, what your actual options are, and the historical context. youtube ipa file for ios 9.3.5