Hey, you don’t need a poweramp to play live. You could use a Full range/PA speaker for monitoring (i.e. Yamaha DXR10, Headrush FRFR108 or 112 etc).
If you want to run a cab on stage with Kemper, you’ll need a poweramp.
Yes, you could run Kemper into Effects Return of Laney head, to use the poweramp section only, then run into a cab. I would not run Kemper into front input of head.