Q: I agreed to update my ipad today but now I can't get back in.

See if any steps in the article help. Or you may simply have to wait and see if it resolves itself

https://support.apple.com/en-us/HT206203

Fixed the problem on my ipad2...the workaround is as follows:

a) Connect the iPad to iTunes on your computer using the cable

b) Switch off the ipad while still connected

c) Press the on/off switch and the home button at the same time until you get the apple logo followed by the charging cable logo pointing to itunes

d) The iPad will now be detected by iTunes

e) Use the restore option

My ipad2 is now on ioS9.3 and it works just fine !!!!