Do we say " will be started" or "will be starting"
Can you give the context?
The meeting will be starting promptly at 9 a.m. is more natural to me, but "will start" is better yet.
If someone is an agent of the starting - someone will fire the starter's pistol or ring the bell to mark that start, then "be started" would work as well.
Something/Someone will be started (by something/someone else)
The race will be started by Terry Waite near his Blackheath home.
Something/Someone will be starting something/someone else.
Carnival Queen Lisa Stevens will be starting the race at 10.30 a.m.