Thank you so much for playing, I'm so glad Wanderer is your favorite! 🤍
Here are the hints for you:
Ending 9: First, make sure to buy his favorite tea at the kiosk. Then, agree to go to the laboratory with him and read all the pages of his notes on the table. (If you are playing on the hard mode, you'll need to let the timer run out) 😉
Ending 10: Just unlock the previous 9 endings first, and the game will take care of the rest.
Good luck!