Jump onto the roof of the boat in the canal. Then just under the overpass (as you're heading out to sea) jump up to where the coin is. Use hover to get you in the door fully. You're now in a Giant Pachinko machine!!

Go over to the left to where the ball would get "launched" - the red square. Jump on it to launch up as if you were the ball. You get 3 automatically by launching. Just 5 to go.

Note, if you get to the very BOTTOM of the screen without going into any chute, you die!

Just launch up. You'll land on a nail. You can then fall left or right to the lower two purple spots. So far so good. You can also get the lower right one by hovering up the back slide and getting it.

To get to the 2 top ones, you can wall jump up between the wooden back of the game and the transparent glass front! You can also start water-blasting near the top of the launch chute to get the top left one.

Avoid the front/back wall when trying to hover.

Now a shine appears in the center!!

Super Mario Sunshine Walkthrough