Just the cpu? Or both cpu and gpu? IMO a 240mm would not be sufficient for both a 9900k and a 1080. Especially considering how hot a 9900k can run, it may be borderline, although acceptable for just the cpu. I'd consider going with a different setup with a 360 rad.
Try Ek calculator for components vs wattage, it'll tell ya how much radiator you need. Just for reference I run a 240+360, and my cpu is not nearly as hot as yours. That's for a 7700 and a 2080.