Please recommend small Arduino board for single servo drive

Hello all. Newbie here. Have a project - a prototype toy/game design - which requires the movement of just one servo to release some spring loaded plungers after a randomized period of time. Think I am best to use an Arduino to run the timing software and drive the 5V servo. Need a small-ish package - not a full size board. Seems like the Micro, ProMicro, Mini, ProMini, or Trinket are all possible options. We need to be battery powered - either 9V or a pack of AAAs. YOUR EXPERIENCED GUIDANCE APPRECIATED !! Thanks.

Hello. Personally, if size is such a critical factor, I recommend a Pro Mini and a FTDI breakout board to go along with it.

I would use a Pro Mini and a CH340 USB to serial converter (because they are cheaper and not prone to fakes) and if you don't need much servo power a micro servo such as the Tower sg90 9 gramme servo.

Thank you both for the input. 2 for 2 on the Pro Mini. Likely to go that way unless some other strong opinions emerge.