Yes and no ![]()
In the same project you can make 1 pcb for each hierarchical sheet, yes.
Just make a closed pcb outline for each hierachical sheet.

You will have only one BOM. You can make a panel with all the pcbs together too.
So far, so good.
Now, if you want different Gerber files for each pcb you will need to split the layout into the different pcbs. Then, make a number of copies of the .kicad_pcb file and delete what is not needed to generate the Gebers for an individual pcb.

