Older iPhones and iPads can struggle to render the transparency and blur that gives the illustion of depth on iOS 9. You can disable this feature and speed your device up.
1. Click Settings
2. Scroll down and click General.
3. Tap Accessibility.
4. Scroll down and tap on Increase Contrast.
5. Tap on the Reduce Transparency toggle to enable it.
6. That’s it!
If iOS 9 still seems slow try the next fix on the next page.