Once your player/virtual pro reach level 5, you can unlock player celebrations. Upon reaching this level, all you need to do is go to the Edit Player screen and click the Celebration tab. Select and apply any of the celebrations listed here, and wait until your player scores their next goal(s).
Note - The celebrations are performed randomly and automatically. This means that the celebration you chose may not be performed the very next time your player scores, but they will perform the celebration eventually, and the trophy will unlock.