Most National Merit Scholarships are NOT something you can defer for a year, unfortunately, but you could contact individual schools to be sure.
If your student does not yet have a First Choice school for National Merit, leave it as Undecided for now. We had worried that schools might take the listed “First Choice” school into consideration when making acceptance and merit decisions, but that doesn’t seem to be the case.
Here is a thread dedicated to the NMF/NMSF Big Merit schools and their vibes/strengths: Big merit NMF/NMSF schools and their specialties