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iOS 9 comes with some new preinstalled app from Apple. Those applications can't be deleted or reinstalled. To delete third party applications, tap and hold down your finger on the icon and they will start wiggling. Tap the x icon over the icons to delete them.
Re the charging issue, we can reset your iPad and see if it works or not. To reset, press and hold down the Power button and Home button at the same time until it shows the Apple logo. When you see the Apple logo, release the buttons and let it boot.
Then go to Settings > General > Reset and tap Reset All Settings. Then go to Settings > General > Background App Refresh and turn it off there.
Please let me know how it goes.
Please let me know if that didn't work, so we can continue troubleshooting.