Like all ACA grid objects, a Ceiling Grid has a Cell component, which marks the center of each cell in the grid. You may not be aware of this component, since, in the out-of-box Display settings, this component is turned off. It is also mapped to a non-plotting layer (G-Anno-Nplt for US imperial content), so turning the component on will not affect the final plotted output.
The Cell component displays as a circle at the center of each cell in the grid. You can use the CENter OSNAP to place ceiling objects at the center of a ceiling panel.