Can I claim that a hot dip Aluminum coating in steel provides cathodic protection to a substrate since Al can act as sacrificial anode?
In practice, no -- at least, not at ambient temperature.  Aluminum passivates and this passive film breaks the potential electrochemical circuit.  The passivated aluminum can't react to release electrons to the steel.  For cathodic protection you need something that will corrode instead of the steel, meaning it can't passivate.

Usually, cathodic protection is offered by zinc which has less driving force, but it does not passivate and thus the electrochemical circuit remains intact.

Addendum:

Aluminizing does offer cathodic protection at high temperature where the passivation is less effective.