the word "crucified” itself implies death
"Died" is in the creed to show that not only did He suffer the pains of crucifixion (a form of torture), but He also died from crucifixion.
The Catechism of the Council of Trent (Roman Catechism), "Article 4: Suffered under Pontius Pilate; was crucified, dead, and buried," explains this part of the creed thus:
Christ Really Died
The pastor should explain that these words present for our belief that Jesus Christ, after He was crucified, really died and was buried. It is not without just reason that this is proposed to the faithful as a separate object of belief, since there were some who denied His death upon the cross.3 The Apostles, therefore, were justly of opinion that to such an error should be opposed the doctrine of faith contained in this Article, the truth of which is placed beyond the possibility of doubt by the united testimony of all the Evangelists, who record that Jesus yielded up the ghost. (Matt. 27:50; Mark 15:37; Luke 23:46; John 19:30).
Moreover as Christ was true and perfect man, He of course was capable of dying. Now man dies when the soul is separated from the body. When, therefore, we say that Jesus died, we mean that His soul was disunited from His body. We do not admit, however, that the Divinity was separated from His body. On the contrary, we firmly believe and profess that when His soul was dissociated from His body, His Divinity continued always united both to His body in the sepulchre and to His soul in limbo. It became the Son of God to die, that, through death, he might destroy him who had the empire of death that is the devil, and might deliver them, who through the fear of death were all their lifetime subject to servitude. (Heb. 2:10, 14, 15).
Christ Died Freely
It was the peculiar privilege of Christ the Lord to have died when He Himself decreed to die, and to have died not so much by external violence as by internal assent. Not only His death, but also its time and place, were ordained by Him. For thus Isaias wrote: He was offered because it was his own will. (Is. 53:7). The Lord before His Passion, declared the same of Himself: I lay down my life, that I may take it again. No man taketh it away from me: but I lay it down of myself, and I have power to lay it down: and I have power to take it up again. (John 10:17–18). As to the time and place of His death, He said, when Herod insidiously sought His life: Go and tell that fox: Behold I cast out devils, and do cures today and tomorrow, and the third day I am consummated. Nevertheless I must walk today and tomorrow, and the day following, because it cannot be that a prophet perish out of Jerusalem. (Luke 13:32–33). He therefore offered Himself not involuntarily or by compulsion but of His own free will. Going to meet His enemies He said: I am he (John 18:5); and all the punishments which injustice and cruelty inflicted on Him He endured voluntarily.