Once you have beaten all three planets (jungle, fire, ice), take the three knights with you. They will suggest looking for a giant asteroid, so go to the Asteroid Belt in the low left side of the solar system. At X-11 Y-82, there is a giant planetoid with a castle.
Go to the Golden Key and draw it out, and it opens the portal to another galaxy, where the Binary Bard has taken the Princess. You will have to enter the Bard's castle and defeat his robot warrior suit.
(for solutions, see the related questions)
all you get is the island medallion and 100 credits
The 9th Island was Astro Knights island released in 2009. (see the related question)
well just beat the stupid thing ingnore her baby birdies
Wimpy Wonderland Red Dragon Island Counterfeit Island Mythology Island Astro Knights Skullduggery
well just beat the stupid thing ingnore her baby birdies
you jump over it
Defeating Mordred and his warrior suit wins the island, and you receive the Island Medallion and 50 Poptropica credits.
Only by telling you how. (see the related question)
There is no easy way. (see related question)
no, there is not
The only monsters to beat with a bomb are on Astro Knights Island. (see related question)
There are written solutions are the Related Questions below. There is a video walkthrough at the related link.