You do realize that KIX is only 75 minutes away from Kyoto Station by JR Haruka? It is anywhere from 30 to 55 minutes from various places in Osaka.

I've never understood the rationale of moving hotel to Osaka from Kyoto just to spend the night before departing from KIX. Even morning flights are easily reachable from Kyoto on the morning of, and you can shower in your own hotel room before leaving. Shoot, for afternoon flights I've departed to KIX from Okayama and even Fukuoka before flying out.