Unable to get automatic updates for apps?

Turn your device off and back on. If this doesn't help, sign out from your account and sign back in.

Also, you can try resetting your settings.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

Alternatively, you may go to Settings - General - Reset - Reset All Settings

https://support.apple.com/en-us/HT201559

Hey you can check your setting again. Its look like that you update iOS 9 and your default setting was changed

Check setting ->>> iTune & App Store

Sign in firs

And Turn On content that you want to automatically download turn on to Apps

Now Save and Exit

You are welcome.