I'm often working with displays that are receiving content rendered as rec709. However, the content creator's displays are not calibrated to rec709. My displays are on camera and shot for broadcast, and we're delivering rec709. How should I be handling this when creating LUTs ?

Sorry, I actually do not follow what you are asking?

If the content creator's displays are not calibrated, the content they are generating will nit be Rec709.
So it will look wrong on a calibrated Rec709 display.
So exactly what LUT are you talking about generating - to do what?
If you can explain further I can likely help.

Steve