The poem suggests that the love of the poet is dancing on her wedding party, while the angels sob and groan during the overwhelming noise of the drums and pipes. Again, this gives the a tension also expressed in "Ich grolle nicht" (song 7). Is it really that the angels are groaning, or is it that the poet hopes they are, hopes that she is not happy.
The tonic, d minor, is again related to the tonic of the song before, a minor.
In song 9 the piano has the melody, with the singer having a counterpoint melody. Recognize the dissonants in the first measure, where the chord on the second and third beat is a diminished chord, while the first beat suggests an a chord. If you leave out the Bes in the diminished chord, there is just a plain A7 chord, going towards d minor, the tonic of the song. But except for these embellishments, the harmony is very clear.
The harmony in m. 8-12 is the almost the same as the harmony in m. 24-29 of song 8: A7-g7, C7, F7.
The first two lines of the song go to the F chord in m. 16. The second verse is a fifth lower and starts in m. 16 and continues till Bes in m. 32. The harmonic move in m. 24-29 D-g-C7-F7-Bes-Es towards "Herzallerliebste" where the harmony goes back to the tonic F and in the interlude goes through Bes to a surprising E, A till a diminished chord in m. 35.
The postlude starts with a repetition of the prelude in m. 68-71, and then continuous with a repetition of the interlude of m. 17-20 in m. 72-77. M. 77-79 have an interesting aspect; the first tow beats are clearly D, but then we have in the right hand a solution to A and in the left hand to g on the last beat is D the dominant of g (as suggested in m. 74-5), or is D the tonic with A as its dominant and g as its IV. The end line, a chromatic scale downwards in D with Fis remaining in the upper tones, suggests D. But the use of Eis (not part of D) instead of F (part of D) may suggest that Schumann was thinking differently.