Xcode update is stuck at waiting

This is something that happens often and I wanted to make sure you are going to fix this the right away, without causing any problems to your system and save you some time. 

This was written for Xcode 8.3 (but it has worked for previous versions as well) and it is confirmed that it works on:
OS X 10.10 Yosemite, OS X 10.11 El Capitan, and macOS 10.12 Sierra.

I am assuming that you are at your Updates screen and Xcode is stuck at "waiting". Click on Xcode (the actual name/caption of the pending update) and the relevant page of Xcode on App Store will show (see below). 

When you click the Update button (beneath the application icon on App Store), a little progress bar appears beneath it, and it usually tells you "less than a minute" (but it is stuck there forever). 

Don't navigate away from this screen on App Store, because we want this little progress bar to be our indicator on what is happening. 

• Open a new Finder window and click Applications (top left hand side). 
• Scroll down to the Xcode application and drag the application to Trash.
• You will be asked to confirm your password before moving Xcode to Trash.
• Once you enter your password, there will be a prompt asking you if you want to cancel the update or delete the app. Choose delete. 
• You will notice that immediately after clicking delete, xcode starts downloading the updated version, and you can see/confirm that at the progress bar (as discussed earlier on) and it will tell you how long it will take (it can take an hour, depending on your Internet connection).
• (optional) If you want to save some space on your disk, go to Trash, right-click on xcode, and delete it completely from the system. It will ask you again to confirm your password. 

Don't forget to plug-in your computer, as the whole process takes a while, and the computer might go to sleep and suspend the download and/or the installation.