Where is the sun at noon in September?

At noon, the Sun would cross the meridian, wherever you live.

September is close to an equinox; if you live at the Equator, the Sun would be at the zenith. For every degree further north that you live, the Sun would be a degree south of the zenith. For example, if you live at 50 degrees latitude North, the Sun would be 40 degrees above the horizon (towards the South) i.e., 50 degrees from the zenit.