Hey RubyDev!
Does this issue occur only within the web app, or in the engine/game?
I just wanted to mention that error 409 will show up in the web app if you try to submit an entry with the same name because it will try to create an entirely new instance of an entry with a new unique identifier. However, inside the engine/game it should allow you to change or submit an entry with the same username, without causing the 409 error, unless you have cleared the PlayerPrefs.
I have also just released a new update which allows you to store the player's unique identifier in the persistent data path, rather than PlayerPrefs.