You can only get the 24 hours pass on board - not in the planner pre-cruise.
You can get about 15 min of free internet by clicking on the App/Play store link on the screen where you would set up internet.
Welcome to CC.
Turn on Wifi calling on your device before you leave for your sailing and practice using it (plane mode, wifi only). Then, in ports, follow the ship crew to the nearby free wifi hot spot and check in with the family.