Yes, Oppo F9 does have the OTG support.
No. Oppo F9 does not have the NFC support.
Oppo F9 has the aperture of f/2.0 for its 16MP front camera.
Yes, Oppo F9 does have the fingerprint scanner.
The most striking feature of the Oppo F9 is the big display with the waterdrop notch. It is well designed, delivers good battery life, and offers decent performance for the price.