Is the Pope the Man of Sin in the Bible?

Yes.

The Bible plainly states that the “man of sin” opposes and exalts himself above God, that he as God sits in His temple, and shows himself that he is God:

2 Thessalonians 2:3-4 King James Version (KJV)
3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
4 Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God.

Pope Leo declared that Roman Catholicism holds the place of Almighty God:

Pope Leo XIII, Encyclical Letter of June 20,1894
“…We hold upon this earth the place of Almighty God…”

Jesus professed that no man is to be called father upon the earth, but only our Father in Heaven:

Matthew 23:9 King James Version (KJV)
9 And call no man your father upon the earth: for one is your Father, which is in heaven.

Pope Pius XI claimed he was “the Holy Father” and that he was “god on Earth”:

Pope Pius XI (April 30, 1922):
You know that I am the Holy Father, the representative of God on Earth, the Vicar of Christ, which means that I am god on Earth.

Jesus affirmed that people simply reject the commandments of God in favor of tradition:

Mark 7:9 King James Version (KJV)
9 And he said unto them, Full well ye reject the commandment of God, that ye may keep your own tradition.

The most beloved Pope John Paul II instructed his followers to have no fear when people called him “Holy Father”, and even quoted Matthew chapter 23 verses 9 and 10, which is a complete contradiction against his own words, and he uses “tradition” as his excuse for the blasphemous titles:

John Paul II, Crossing the Threshold
“Have no fear when people call me the ‘Vicar of Christ,’ when they say to me ‘Holy Father,’ or ‘Your Holiness,’ or use titles similar to these, which seem even inimical to the Gospel. Christ himself declared: ‘Call no one on earth your father; you have but one Father in heaven. Do not be called “Master”; you have but one master, the Messiah’ (Mt 23:9-10). These expressions, nevertheless, have evolved out of a long tradition, becoming part of common usage. One must not be afraid of these words either.”