Jamieson, Fausset and Brown on Isaiah 14:9

9. moved--put into agitation.

for thee--that is, "at thee"; towards thee; explained by "to meet thee at thy coming" [Maurer].

chief ones--literally, "goats"; so rams, leaders of the flock; princes (Zec 10:3). The idea of wickedness on a gigantic scale is included (Eze 34:17; Mt 25:32, 33). Magee derives "Rephaim" (English Version, "the dead") from a Hebrew root, "to resolve into first elements"; so "the deceased" (Is 26:14) "ghosts" (Pr 21:16). These being magnified by the imagination of the living into gigantic stature, gave their name to giants in general (Ge 6:4; 14:5; Eze 32:18, 21). "Rephaim," translated in the Septuagint, "giants" (compare see on Job 26:5, 6). Thence, as the giant Rephaim of Canaan were notorious even in that guilty land, enormous wickedness became connected with the term. So the Rephaim came to be the wicked spirits in Gehenna, the lower of the two portions into which Sheol is divided.