Here is the full list of all 9 Detective Grimoire achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Draw a cute ghost in your notebook
Complete the game 100%
Full suspicion on the culprit, none on anyone else
Get inside the tent
Examine all the Boggy merchandise
Complete the game
Finish speaking to the Little Girl
Read the letters on Remington's desk
Examine the crime scene