I have all 9 pieces.

On the Games page under Collection, there's a link to the treasure maps page.

Here's a direct link for you: click

LOL OH MY GOD

You recieve 12,284 sP and:

Marsh Plush Stuffing

Berrymint Tights

Starfruit Sticker

Common Noktoa Plushie

Dark Brown Bookworm Styled Locks

That was NOT worth it! But thank you for the help! <3

yeah it's only really worth it for the achievement and access to the blue building 😞