As the OP, I appreciate the feedback. Have already reached out to my concierge and plan on contacting the hotel a couple of day prior to arrival. I didn't realize my "early" 9am check in request doesn't compare to some of your ultra early check in requests. To me, the biggest factor will likely be availability. I just wonder how often hotels are really truly 100% sold out. I often hear FD agents say "we're full" tonight...but not as often do I hear how full or that they're completely sold out.