While you're correct about "Going Home" being based on the slow movement of Dvorak's Ninth Symphony (using the correct chronilogical numbering of his symphonies), you are, I believe, incorrect about the derivation. Dvorak undoubtedly was influenced by the American music he heard during his time here in 1890's. But the music in the slow movement of the symphony "from the New World" was completely original; it was not taken from any specific spiritual or any other direct source. The "Going Home" text was added later to Dvorak's music, if I remember correctly.