From videos of both the SES-10 launch shown in @RusselBorogrove's question, Cause of apparent plume deflection on SES-10?" and the Block 5 launch Bangabandhu Satellite-1 Mission at
T+ 01:48 it appears the Falcon 9 uses non-zero angles of attack (or displacement angle) during the 1st stage burn.
The exhaust plume is aligned with the flight path (high dynamic pressure) and it's obvious the vehicle's roll axis isn't.
The accepted answer states:
I believe the visual effect is due to the rocket flying a small positive angle of attack at the end of the first stage burn, combined with a steeply foreshortened camera view.
According to the simulation data at FlightClub (https://www.flightclub.io/results/?code=SS10), the rocket flies a positive angle-of-attack during the end of the first stage burn, peaking at about 4.6 degrees AoA.
Is this advantageous?
left: screen shot from Bangabandhu video, right: SES-10 from here. Click for larger size.