Using the highest possible DPI setting may be counterproductive - there is no point scanning at a resolution much higher than the original document.
I have scanned old photos and got perfectly acceptable results at 300 DPI.
If you scan at say 9600 DPI, the scan will take forever, the resulting file will be enormous, and probably be too big for many photoediting applications to handle, and if it can be handled, will take ages to edit.
Do a test - scan 1 photo at 300, 600 then 1200 DPI.
Look at the file size produced.
Try editing each one.
Note the speed of the editor.
Try printing each one at double size.
I suspect you may possibly see a slight improvement by using 600, and no discernable improvement at 1200.
I doubt there will be any difference whatsoever above 1200 - assuming you print on the C4280, that has a maximum printing resolution of 1200.