A:AnswerI do not have the Galaxy Note 9 but I do have the Galaxy S9 plus and it works with that, check the measurements. I has to be the measurement for the long length of the phone.
A:AnswerMost functions I need are there and accessible from the gimbal or screen EXCEPT for switching front to back cameras. If you want fine control of your phones' functions Filmic Pro is a good choice.
A:AnswerDepends on the festival. Most events don't let you take in interchangeable lens cameras as it's considered "professional" regardless of the sensor size. These usually get in no problem. E-mail the event team to be safe.
A:AnswerIt can be used with or without DJI app. You will have to control the gimbal manually and will loose some app features like auto tracking and othe app specific features.