WI-Cruiser

If this on board credit is from the Royal Caribbean Credit Card, then the OBC usually doesn't show up until about 2 weeks out from the cruise, maybe even closer. If from something else I'd give them a call as you should be able to see it in the cruise planner.

As others have said, any specialty restaurant can make you reservations for the week. If there is much of a line at the nearest restaurants (likely Wonderland or Jamie's) head forward to Chops - farthest from boarding location and thus less likely to have a line. Reservations can also be made in the app but I've found it easier to deal with a person at a restaurant, but nothing to stop you from making the reservations you can in the app while waiting in line.