"Strut off" means to leave a location with a strutting gait, not arrive at a location. I don't think that makes sense, given your intent.
("The autumn strut(s) off" is five syllables, not four. )
In English, leaves falling from the trees at Autumn is usually pictured as a type of dying, not a proud parade away from the trees to the ground. It's in interesting image, but I think it would take more than four syllables to get it across.