Yorkey's Knob, Jan 2018
We took the GBR cruise back in Jan 2018, so my information is a bit dated. When Solstice overnighted at Yorkey's Knob (Cairns), the last tender from ashore was scheduled to leave at 10:30 pm local time. Tendering was then scheduled to resume at 7:30 am the following morning.
However there were passengers like my family that had made independent arrangements at Cairns and we needed to be off the ship early in order to be there on time. So with little announcement/advertising, Celebrity arranged for a couple of very early tenders to get us off the ship. No guarantees that you will see that arrangement on your cruise, but you should inquire if this is of value to you.
Hopefully for you, the tender/shuttle schedule is what Jim posted earlier.
If you are interested, here is link to the folder of all the Celebrity Todays that were issued during our 12 night GBR sailing. Also I published a photo review of our cruise that has some information that may be useful for planning even though it is dated and on a different class of ship.