Keep in mind that the Pixel charger uses a function of voltage and current. So, be aware that chargeres that deliver high wattage may not do so at the voltage required to charge the p9XL at it's fastest rate.
PD: 5V/3A, 9V/3A,15V/3A, 20V/2.25A
PPS: up to 11V/3A, 16V/3A, *21V/2.25A max 45W*