If your iPad is disabled, the only way to unlock it is to completely erase and reset it. If you have a backup, you'll be able to restore it, otherwise you'll lose all of your data. There is no way to unlock a disabled iPad unless you use the correct passcode or you erase it. And the following guidance will show you how to unlock a disabled iPad with iTunes.
Step 1. Connect your iPad to the computer with via a USB cable that your iPad has trusted.
Step 2. Launch iTunes. If you've synced your iPad with iTunes, then no "enter password" is required.
Step 3. iTunes will automatically sync your iPad and create a backup file. If it doesn't, you should sync your iTunes and create a backup file manually by clicking "Back up Now" in the Summary window.
Step 4. In the Summary window, you can see the option "Restore iPad". Click it to reset your iPad. Once the reset process is complete, you'll be taken through the iPod's initial setup process.
Step 5. Select "Restore from iTunes backup" during the setup process. This will load the backup that you created so that all of your data is restored.