RankTrials was a plugin that was made for this request. It was originally going to be called StaffTrials, however it now has many uses and can be used to count down kicking a player or banning a player by running the commands.
sTrial.Admin - Permission to run the command /sTrial
/sTrial add <TrialType> <Time> <Player> <Command> - This adds a trial to a player and performs the command when the time is met. The command supports spaces, but can not include a / in the beginning.
/sTrial cancel <Player> - Cancels the trial of the specified player. Will force run the command that was defined for that sTrial right away.
TimeExpired: '&4Your trial has ended for your staff rank! :( &aWe will get back to you on how you did soon enough! :)'