Waxing acts as a sealant on your car's paint and protects it, it can be done everyday even or should be done after every wash. Our local people tend to call waxing "polish".
Polishing itself should be done after six months or so, it does however cut a thin layer of paint and that's why it should not be done so often. Our local guys tend to call this process "compound"
You should apply some compound "polish" on your bonnet and if the scratch is light enough it will come off, whatever the case apply some wax afterwards to seal the paint and give it fine finish.