How to correctly say time in English?
Solution 1:
Welcome! The only issue I see in your phrasing is the preposition choices. Some of the choices are not technically wrong but are not natural use to this American at least.
“The meeting will be held at 30 in the morning on September 12, 2019.”
Note: you can say “on the morning of September 12,” but usually when a time is included, we say “on” because “in the morning” goes with the time. When there is no time, it becomes “on the morning of...”
“I will be travelling on business on September 30, 2019.”