What I've tried so far in the following order:

- Update graphics driver
- Update sound card driver
- Re-install FFXIV
- Install older graphics card driver
- Update BIOS
- Re-install FFXIV
- Re-install Windows 10
- Re-install all the drivers from manufacturer's website
- Re-install FFXIV
- Install older sound card drivers
- Downgrade BIOS
- Re-install FFXIV
- Install virtual sound card
- Delete virtual sound card
- Re-install FFXIV

None of these seemed to work. Bear in mind that I made no changes before this error started and I managed to play completely fine before that.

DirectX9 hasn't crashed on me yet, but I've only managed to do 2 duties with my limited time this week.

I also tested some games that should be running DirectX11 and none of those crashed.