I would go for the Z390 chipset motherboard instead of a Z370, so you will need to pick Asus Maximum XI Hero. The Z390 will have compatability out of the box, but much more important is that the board is better designed for the 9900K, the VRM's will be able to hold the large temperatures of the 9900K, so better OCing performance. Small price to pay to have a much more stable rig