Stoves too big for the hole, I agree.
9KW is just crazy!
My little Stockton is only 3.75KW and really kicks out the heat.
How big is your lounge?
3.75kw wouldn't do it for us mate, we like to leave the doors open and have this take almost all of the strain off of the oil burner heating system. Later this will actually be connected to that and will heat that loop too.
Lounge is currently (I say currently as we are going through some building plans currently) roughly 36*16, while not huge it's probably a bigger area than most but more importantly it has no insulation really and the heat wafts all over the house