(Please forgive my English)
I've begun this episode today and i'm now stuck like you ! I've got the same problem, I cannot use the 9th switch. Before that, I'm stuck when I use the pen on the notepad : I can't move, and I can't use anything ! I've already tried to rewind, and I've deleted the game and re-downloaded it but it didn't change anything...
Maybe a recent release did that ?