A basketball with more air will be bouncier. Unless a ball is very flat, I don’t expect the air pressure to have a noticeable effect on how it feels to shoot the ball, or how it moves through the air. However, since a very full basketball will bounce a lot more on the rim, it might be harder to score.

I don't think it does. Air pressure in a basketball will cause the ball to deform more, which might increase its air resistance, which could affect the shot. More importantly, air pressure affects the ball's bounciness, making it possible to dribble.