"#9 Dream" came to Lennon in a dream. Lennon has said that the song was just "churned out" with "no inspiration."
That's what I call craftsmanship writing, meaning, you know, I just churned that out. I'm not putting it down, it's just what it is, but I just sat down and wrote it, you know, with no real inspiration, based on a dream I'd had.
According to May Pang's website, two working titles for the song were "So Long Ago" and "Walls & Bridges". Pang also states that the phrase repeated in the chorus, "Ah! böwakawa poussé, poussé", came to Lennon in a dream and has no specific meaning. Pang added that Al Coury of Capitol Records initially protested against the use of the word "pussy" in the chorus, but after Lori Burton, the wife of studio engineer Roy Cicala, suggested that it should be sung as "poussé," as if in a foreign language, the lyrics were kept.
The song was notable as a favourite of Lennon's, despite his later claim that the song was a "throwaway." Pang said on the matter, "This was one of John's favorite songs, because it literally came to him in a dream. He woke up and wrote down those words along with the melody. He had no idea what it meant, but he thought it sounded beautiful."
The backing vocal is provided by May Pang, Lennon's partner at the time. Lennon wrote and arranged the song around his dream, hence the title and atmospheric, dreamlike feel, including the use of cellos in the chorus. The song is also much more heavily produced than most songs that Lennon produced.