iOS 8 and problems with iWork's accessing iCloud
It seems that you've inadvertently upgraded yourself to iCloud Drive via Pages for iOS on your iPhone, but not on your iPad.

To activate iCloud Drive on your iPad, follow these steps:


Go to the Home Screen.
Find and open Settings.
Scroll down to iCloud, and tap iCloud.
Tap iCloud Drive.
Toggle the switch to the right of the text "iCloud Drive" to the ON (green) position.