Yes, it is known that at least in his time as the Thomas Cantor in Leipzig he was a music teacher in great demand. It goes without saying that this it true beyond his appointment, but as aside of his duties in church and to teach at the St. Thomas School. Just teaching Latin wasn't Johann Sebastian Bach's "cup of tea". This part of his job is, what he deputed to a fellow teacher - after all for the half of his salary as the Thomas Cantor.
99 Music Calendars, Composers Calendars and Bach Calendars