N.G.
I had tubes in my ears at age 11, so no, your child is not too old. However, sometimes if you wait, their eustacian tubes can correct themselves (mine obviously didn't), but the concern there is that they will have already had speech issues by the time their eustacian tubes are fully developed so its preferred to get tubes before then, if that makes any sense.
Ear drops will clear away outer ear infections, but not 'deeper' ear infections.
Saline spray in the nose (or a netti pot) can clear the sinuses by flushing them out. It works very well for the sinuses but does not help the ear properly drain fluid.