--"Iblis" is not from "mala'eka" (angles), but a "jin" according to the exact quote of Quran (18:50), and "jin"s do have free will, unlike "mala'eka" (angles). all the angles did bow down to Adam, again according to the exact quote of quran (15:30 and 38:73). Here is an explanation about why usually, and mistakenly in my opinion, "Iblis" is considered as if he is an angle or as if he was ordered to bow down to Adam too. The story says: God orders "angles" to bow down to Adam (not "iblis"! he isn't included. but he was a member of God's court and therefore present during this scenario), they "all" do, and "iblis" refuses. this "refusal" is not, by itself, the reason that God rejected him from himself, after all he was not included in the given order. but his explanation, when he reveals his racist nature (he is from "smokeless fire" and Adam from "mud", so considers himself higher), then God rejects him from his court.