Question Is this an adequate MOBO for the i9 9900k?

[EmptyCoconut]

I'm considering buying an i9 and the asus rog maximus x code.

 

[Calvin7]

Yes, it needs to have BIOS version 2003 or higher for that CPU.

You can use USB BIOS Flashback to update BIOS.
How to Use USB BIOS Flashback - ASUS