OK, so need some clarification about the last two statements:
I Have tried the following and still failed to upgrade:
a- Upgrade my iPad to iOS 8 by using iTunes 12.3.2
b- Upgrade my iPad to iOs 8 by using iTunes 10.6.3
How did you go about trying to upgrade your iOS to anything other than 9.2?
Is your device jailbroken?
Have you tried backing up your device to, say, iCloud, then erasing the device, updating the "clean" device, then restoring it from the backup after you have successfully upgraded?
Here is the Apple Support take on an error "9":
Errors: 2, 4, 6, 9, 1611, 9006.
Sometimes security software can stop your device from communicating with either the Apple update server or with your device.
Check your security software and settings to make sure that they aren't blocking a connection to the Apple servers.
If you still see the error message, check for USB connection issues.
Errors: 13, 14, 1600, 1601, 1602, 1603, 1604, 1611, 1643-1650, 2000, 2001, 2002, 2005, 2006, 2009, 4005, 4013, 4014. You might also see a message that includes "invalid response."
If the USB connection between your device and computer is interrupted, you might not be able to update or restore.
To narrow down the issue, try different equipment:
Cheers,
GB