Unbricked iPad from bug Jan 1 1970 by Upgrading to iOS 9.3
I had to put my iPad to DFU Mode then download iOS 9.3 Beta 4 from Apple developer site then everything is fixed. Do not need to unplug the battery, because iPad Teardown is very hard, it's easy to break the screen. For some one else who still facing with this problem, try to upgrade your ipad.
Apple has fixed the problem. Now, you can not set the date before Jun 23, 2002.