Samsung Adapter charging Apple Watch series 6

Hi.

I know there is much about this online but answers seem to vary.

Is it safe, and is there any real difference in charge speed in using a 9V Samsung adapter to charge a series 6 Apple watch, in comparison to the 5 Watt Apple adapter?

Thanks

Samsung adapter - https://www.kogan.com/au/buy/samsung-usb-fast-charging-travel-adapter-9v-black-samsung/?utm_source=google&utm_medium=product_listing_ads&gclid=Cj0KCQjwlvT8BRDeARIsAACRFiVh2bZ5oWKhZy79oSMj1CgrdswPpIw0NQnYN-JUIuENIZX2_L7l1lwaAgViEALw_wcB