I would rather trust the manufacturer. So the standard is POE (802.3af).
The maximum power consumption is 9W according to the manufacturer, so POE would also be perfectly sufficient.

Yes, the PoE standard for the Ubiquiti AP Ubiquiti Unifi U6+ is 802.3at (PoE+). The manufacturer's website states that the device is compatible with PoE, but does not specify the standard. The 802.3at standard is the latest and most powerful PoE standard. It provides up to 30 watts of power to PoE devices, which is sufficient for the Ubiquiti AP Ubiquiti Unifi U6+.

Here's some more information on the 802.3at standard:
- It is defined by the IEEE (Institute of Electrical and Electronics Engineers).
- It provides up to 30 watts of power to PoE devices.
- It is compatible with 802.3af (PoE+) and 802.3af (PoE) standards.
- It is used in a wide range of applications, including Wi-Fi access points, IP cameras and IP phones.