Can't update (formerly managed) iPad to 8.0.2 from 8.0
The way to complete this is to locate a downloadable version of the iOS 8 install file.  Redmond Pie has a great blog post with links to each version of the software.  

http://www.redmondpie.com/ios-8-beta-download-release-date-features-rumors-and-news-update/

Once you download the version of 8.0 for your iPad version - following this:

Connect ipad to computer
Click on iPad - Summary
Hold  and click on restore.   A file dialog window should open, allowing you to manually select the restore media.   Navigate to where you downloaded the iOS software to, and select that .ipsw file from the list.  

It should overwrite and install the 8.0 version to the iPad.  

Regards, 

Ed