It starts at 9:00 o'clock.

We should omit o'clock.Am I right？

Question

It starts at 9:00 o'clock.

We should omit o'clock.Am I right？

Answer

"9:00" can be read as either "nine o'clock" or "nine". So, adding "o'clock" is redundant.

Answer

In writing you could clarify, if necessary, by stating ‘am’  [morning] or ‘pm’  [afternoon or evening].
In speaking, we often do say  ‘ . . nine o’clock’, although you can also say  ‘It starts at nine’.

Answer

You could also add AM or PM instead of o'clock. For example 9 am or  9pm.

Answer

Hi, yes, you are correct.
Sometimes we add in the morning or in the evening if not clear.