Yes. It also says so in the description: Charger for connecting and charging compatible devices via USB incl. USB C cable. Or in the specifications under scope of delivery.
You can use it to charge anything that is designed for 5V. This includes your Huawei P30 Pro.
Wherever you heard that from... But you can rely on the following:
- The voltage U[V = Volt] can break your device if it is too high.
- The current I[A = Ampere] determines how fast your device can be charged.
The USB chargers are all 5V as far as I know (if you are in doubt you can read this on the device). For smartphones tablets etc. the same.
BUT...
If you don't use the original charger, your smartphone may not charge at the promised speed:
https://www.androidpolice.com/2019/04/12/quick-rapid-turbo-and-fast-charging-explained-what-you-need-to-know-about-charging-your-smartphone/
I hope this has helped you.
The Samsung Travel Adapter EP-TA20 cable is compatible with the Samsung Galaxy S9 as it has a USB-C port that is suitable for charging devices with a USB-C port. However, it should be noted that the Galaxy S9 has a micro USB port as standard, so an adapter or a separate cable with micro USB to USB-C would be required to use it with this charger.