Is Iblis an angel or a jinn, and how did he disobey Allah if he was an infallible angel, and if he was a jinn, does that clarify his possession of free will?

Iblis is from among the jinn, not from the angels, based on the Almighty's saying: "And [mention] when We said to the angels, 'Prostrate to Adam,' so they prostrated, except Iblis. He was of the jinn and disobeyed the command of his Lord." Iblis was created from fire, and the jinn were created from fire, whereas the angels were created from light. Furthermore, angels do not disobey Allah and do what they are commanded, while Iblis disobeyed the command of his Lord. Thus, he had a choice, like humans and jinn. Some opinions that state he was from the angels are from the Isra'iliyyat (Judeo-Christian traditions) that contradict clear Quranic texts.