Logic and reason and discussion, Socratic dialogue and Vyasan question-and-answer go as far as the limits set by the human brain. At a certain point, the queries stop, the imagination falters, the heart remains unsatisfied. The conviction is partial not total, because the analytic method has not been fulfilled by the mystic visions and intuitive insight.
'The worlds hang on me like pearls on a string' -- was Krishna's poetic metaphor to suggest a mystical truth. He proceeds further now by saying, 'By invisible presence straddles this universe ......' Like the invisible winds reposing in the sky, 'all beings repose in me'. He is referring to the 'yogamaishvaram', the miraculous Yoga by which the invisible informs the visible, the transcendent permeates the physical, the divine irradiates the secular, while remaining 'neutral, unattached, ', unbound (nibadhna). Inapprehensible, we clutch Thee !
The key shloka of Canto IX is number 23 : 'Even the worshippers of images, in reality worship me; their faith (shraddha) is real, though their means is poor'.
It is a magical word : shraddha. The closest English equivalent is 'faith'. But shraddha has associations with darshan, and woshipping a physical image of a non-physical divinity is a form of darshan provided it is done with shraddha. No shraddha is refused : 'I will accept any gift, a fruit, a flower, a leaf, even water, if it is offered purely, and devoutly with love .... No worshipper of mine is ever rejected'.