in category extensions theres 9 endings but there you cant do it with no codes. so why isnt there an 9 endings in this?

9 Endings is only the "easter egg" endings: stuff like the Whiteboard ending and Song/Voice Over ending. You can basically just think of them as the fat of 21 Endings. They're only given their own category in the CE page because it's kinda just as meme :P