Here is the full list of all 20 the 9th day achievements.
Game time breaks through 20 hours.
accomplish all above and get a platinum trophy.
Go through the whole game following the option order.
Game time breaks through 10 hours.
Another story pass.
Collect all CG.
Saki line pass.
Pass Saki line again after passing Another story.
Suzu line pass.
Through the link in game to arrive at the official shop.
Through the link in game to arrive at the official blog.
Through the link in game to arrive at the official website.
Mai line pass.
Occupy all archive places.
Maki line pass.
Appreciation mode all music listen once.
Watch ED for the first time.
Watch OP for the first time.
Prologue finish.
Save the game once.