[Link]

1) X and Y locations are the exact location on the map grid. In-game there's not much you can do with it, save limiting the area of where you're looking for that (hidden) item to a minimum.

2) You can find out about the time of the day by letting you mouse pointer hover over the pause button on the bottom-left side of the screen. It will tell you Day x, Hour y.

3) Waiting just takes longer. It is, of course, possible to do so, but are you willing to stare at you computer screen for 30 minutes in order to skip approx. 15 hours ingame. [NOTE: I'm not sure about the exact time difference between real time and in-game time. Perhaps somebody else knows this?]