Which rapper featured as a guest on the song "Bandz a Make Her Dance" joined the label Cash Money Records at the age of nine?
Bandz a Make Her Dance:  The song, produced by Mike WiLL Made It and co-produced by J-Bo, features guest appearances from fellow American rappers Lil Wayne and 2 Chainz. Lil Wayne:  In 1991, at the age of nine, Lil Wayne joined Cash Money Records as the youngest member of the label, and half of the duo The B.G.'z, alongside fellow New Orleans-based rapper Lil' Doogie.
Lil Wayne