I'm not familiar with the 609 either. But the the rule of diagnosis is "NEVER FORCE ANYTHING". You found out why.
There is a drive gear on the top horizontal shaft that drives a gear at the top of the vertical shaft. There is also a gear at the bottom of the vertical shaft that drives the bobbin hook shaft and two gears at the hook.
Put oil (Tri-Flow recommend) at the bottom of the top vertical shaft gear and at the base of the left (bed) side of the pillar. That will lube the two places for the vertical shaft.
I'm not sure what you want to do with the machine, but carefully lube anything that moves and find out what will move and what wont. Then work with the stuck part(s).
More than likely it was gummed up with old lube. Now it has that problem and busted gears.
Joe