I would stress I have no experience of this device so I'm going by the data sheet.
Yes, it can be turned off internally but if it is a power output, like almost all types of output, it wouldn't assume a high impedance state. Generally it is only inputs that have high impedance so they minimally load whatever is driving them. An input shouldn't be left floating as it could assume any voltage leaked or conducted to it so a pull-up or pull-down should always be present but outputs are normally OK.
Even if turned on internally, without a load it would probably just produce a high level voltage at the output but not draw any additional current.
Brian.