I heard that you can use cheat engine to unlock the the 16:9 aspect ratio. Just gonna post what a Steam user "Rassius" said
"A good friend of mine managed to get the game working in 21:9 without stretching through some tinkering with Cheat Engine. Of course, we don't know if it will work flawlessly during the entire game because of the pre-rendered scenarios, but it's a start. Proof here
http://imgur.com/6ZJBCQe (it's a screenshot he sent to me).
I don't know the exact details, but I know he did something similar with FF XIII and wrote a guide about it. Maybe it could help as a reference."
But ya Cheat Engine could do if you can toggle between the locked/unlock the the 16:9 aspect ratio ingame. I might just play it on 4k TV instead as it's seems its gonna take a while to get 21:9 working fix. Thx for tip mvfcarvalho although.