On Android for free apps I believe the default is no password confirmation
Assuming recent versions, you could press home + type "Play Store" to search and open the app, search for something and install without a password, assuming an unatended device, in my phone at least you can click to wake up the screen
You can, I just tested, 2 tabs + Enter get you writing on the Search Box
A surprising amount of keyboard shortcuts work on android, Alt+Tab works to get Recent Activities, Directional keys let you move aroud elements, even the special keys like home/calculator work
But there's a lot of unintuitive stuff, back button is Windows + Del
