There's a bunch of catagories surrounding coolers, be it air or liquid. Looks, fit, need, capacity, quality are about the most important. Budget is almost meaningless as a quantification.
Air and aio are the same, as far as ability and capacity goes, in their respective ranges. A little 120mm aio is @ 140w capable, as is the hyper212. On the other end, the NH-D15 is about king of aircoolers, at 250w+, but is equitable to most 240mm aios in ability.
Then there's heat output. The 9700k with OC can top 200w, so the last cooler you'll want is one like the Scythe Fuma 2, at 200w. You'd be looking at very high temps with high cpu loads.
So what you'll need is the largest aircoolers, or a 240mm/280mm/360mm AIO, the bigger you can fit in the case, the better.
And that's where fit comes into play. Some cases won't fit a NH-D15, gpus can interfere, so a NH-D15S is a better choice. Cryorig R1 Universal fits far better than the Ultimate. Some cases won't fit a 280mm aio, but have spacing for a 240mm/360mm instead.
Which brings you to looks. Personally, I'm biased. I much prefer not only the look of the aio, but the software that controls them is far more versatile and adaptable to my tastes than what's available in bios or many motherboard software options. To me (I own both a nzxt x61 and a Cryorig R1 Ultimate) the aio seriously outperforms the aircooler. My i7 went from almost silent at 4.9GHz and 70°C to quite audible at 4.6GHz and 70°C. Even with the lowered OC and corresponding voltages.
So the end result is going to boil down to choices. What fits or doesn't. What looks better or worse. What performs better for your tastes or not. What can you live with.