boot == boo-t
book == buh-k
As a West Coast Merkin, I've never been to Worcester MA but I've made several friends who lived there and in Baaahston. They pronounce it Wuhsta.
I grew up (mis)pronouncing it as War-chester. I'm from the southwest USA originally.
And then my Canadian friend pronounces is Woostar ("boot" sound), just to add confusion.