You don't even need to wait. Time simply passes slower on the ISS. This actually has nothing to do with being in space though. The time dilation is due to the station moving very fast. A car that went around the world every 90 minutes would also experience the same thing. Interestingly though, gravity does also affect time, but being affected by a masses gravity actually has the opposite effect and speeds up time for objects the more they are affected by it. Earth's gravity is so minute, and the ISS is so close to Earth compared to a person on the surface, that this effect is pretty much a non-factor, and time dilation due to relative speed affects the ISS a lot more.
Didn't say it had anything to do with space,... or gravity,... that was just your assumption.
But simply a good example of the relationship between time and velocity,... as you figured out.

