What idiot put so much crap into the original Scottish Glossary that it's barely openable? Someone cleverer than me can do a blue clicky to reference it.
In response to Abby's question:
My best guess is ban'(sters), as in clergymen - particularly given the later reference to preaching. Just a guess though!
... a bit later tonight ...
My copy of this in 1001 Gems of Song (circa 18890) attributes the writing to Jane Eliot, wriiten about 1750 from a few lines of the original. She uses 'banster', perhaps meaning that the younger members of the 'band' have died leaving only the older men to play. 1001 Gems gives no meaning for 'banster; whereas it has an extensive glossary for other terms.
Real scholars of the language will have better knowledge and better resources than I, having started this project merely to throw some light on this mysterious and wonderful language of beautiful songs.
Here's a directory that will load the glossary one section at a time. That should make it easier.