You can get this achievement by following by video guide below.
Note: Some of the holes on this course have wind effects. You'll see that on the video. If you get hit by a particularly strong gust of wind, give the shot another attempt, you may have had bad luck.Edit:
Please see the comment by AStarfox:
I would like to suggest an alternative to hole 9 however. This is an extremely reliable hole in 1 rather than settling for par. What you need to do is look left from the starting viewpoint of the main course and locate the flag from hole 4. Once found, aim ever so slightly right of the flag and shoot with the following power: two bars full and 90% of the third bar. Guaranteed hole in one regardless of the incorrect flag score.I'd like to point out this definitely works, however, the ball needs to go straight in. If it goes 'behind' the hole, it doesn't have enough time to go in, and the game will count it as Out of Bounds. You can definitely get an eagle/hole in one credit for that though.