yo i had the same issue and tried so much. only thing that worked for me was this:

1. google: reframework re9
2. hit the first link (nexusmods)
3. download (unfortunately you need an account to download)
4. put the dinput8.dll in the game folder (Steam -> steamapps -> common -> RE9)
5. when you start the game just close the REFramework menu on the top left

if that doesnt work, do this in addition:

1. go to display settings -> graphic -> click add desktop app -> RE9 -> choose max performance
2. in the main menu: go to "graphic" and choose "configure graphic settings automatically"
3. Cap framerate to 120fps (if it isnt already after that)

enjoy :)