So you are not planning an ATPase assay, but an immunological detection of the protein? Those are quite different things, because not every protein present needs to be enzymatically active. Apart from post-translational modification, some ATPases are sequestered in endosomes when not needed, and transported back to the plasma membrane when required again.
The issue of fluorescence or luminescence is largely one of available instruments, also, for the former you need black, for the latter white plates.