Shore excursions

I am taking my 2nd cruise, going to Cozumel and was worried if I take one of the royal Caribbean longer shore excursions, given it’s to the mainland am i guaranteed to not get left, looking at one of the 9 hour excursions.

Also I’m not fully aware of all the perks for a suite but should i buy the key or is it not useful except for the WiFi. Thank you for you responses.