Unlock achievements without working for them

So, recently I decided to go and start up a server for testing on my old laptop and I started by OPing myself from the command prompt and putting myself in creative. It worked as expected but then when I started grabbing items it gave me a bunch of achievements for doing stuff - e.x. "Cover Me In Derbis" and "Taking Inventory" - and so I came to report it. (I was on an alt that's why I didn't have those already )