Here is the full list of all 18 9 Clues: The Secret of Serpent Creek trophies - there are 2 bronze, 6 silver, 9 gold and 1 platinum.
Unlock every Trophy.
Finish your first Hidden-Object Puzzle.
Complete three Hidden-Object Puzzles without using the Hint button.
Solve three Lockpick puzzles in less than three minutes.
Solve a Puzzle without using the Skip button.
Solve five Puzzles without using the Skip button.
Solve all Puzzles without using the Skip button.
Complete your first Detective Mode.
Complete all the Detective Mode scenes.
Find three Clues connected to your investigation.
Find five Clues connected to your investigation.
Find all Clues connected to your investigation.
Read three newspapers.
Gather information on all of the characters.
Find all nine "clue" objects hidden throughout the entire game.
Save yourself.
Play with Breebo.
Get rid of Breebo for good.