The Samsung Galaxy Note9 keeps itself charged using the Samsung Adaptive Fast Charging Charger that ships with the phone. The charger uses Samsung's proprietary quick charging scheme to charge the phone to almost full in about 110 minutes as observed below.
Upon connecting both the Samsung charger and phone directly using the supplied USB Type-A to Type-C cable, we looked at how the charger supplied power to a dead battery on the phone. About .4 amps current was pulled initially at 5 volts but charging picked up quickly to settle at mostly around 14.2 watts (8.9 volts @ 1.6 amps). After an hour of charging, the phone began pulling lower current to eventually reach around .2 amps as the battery nearly filled up. For more details, download the trace captured by the GRL-A1 power analyzer here.
While the Samsung Adaptive Fast Charging Charger uses 9V charging, the max power consumption is similar to most USB Power Delivery based chargers at around 14W.