One: Align your front chainring with the center of the cassette.
Two: Trim your chain to the minimal amount that will work.
Three: Check your RD's chain tension get it as high as you can without a friction issue.
Four: You'll probably need a chain guide of some sort anyhow, good luck.

A 1x front is a great thing, but once you go past 7 speed it's very likely to have too much of an angle to travel on the outer low/high gears and will probably still pop off unless you have a guide/guard of sort.