Wood changes with temperature and humidity so any instrument will need incremental adjustments over the course of a year.

Fret buzz is caused by either incorrect neck relief, improperly cut nut slots, too low bridge saddles, high frets, warped/humped neck or all of the above.

there's a back and forth method to setting up a guitar that involves time, a small investment in the correct, decent tools and taking the time to properly learn how to do it.

its in every guitarist best interest to know these basics and to know how their tools are supposed to work.

i would recommend that you watch someone like Dave's World Of Fun Stuff to familiarize yourself with techniques. He's a no myth, straightforward, practical kinda guy. Key words No Myth.

short scale guitar necks require more tension to achieve relief. Whereas 9s can be made to work, 10s are recommended while 11s are usually best. Try 10s first. If you go to 10s from 9s you shouldn't have to recut the nut slots and MAY find that your fret buzz is gone if it was a relief issue.