Vs. 1-2 show “thanksgiving” acknowledges one’s faith in God;
Vs. 3-5 show faith in the defeat of one’s enemies;
Vs. 6-10 show the victory is the LORD’s;
Vs 11-20 show praise to God for His righteous judgments.
All praise to God should be with the “whole heart” (vs. 1), not with lips only (Matthew 15:7-9), and God knows the difference as David taught his son Solomon (1 Chronicles 28:9) and the New Testament Apostles acknowledged (Acts 1:24).
Victory is always with the LORD (vs. 3-6) and is so complete that God blots out their name, and the memory of them vanishes forever as God promised (Deuteronomy 32:26). Dead people know nothing of continuing life “under the sun” (Ecclesiastes 9:5-6), and the living will forget those who are dead. This humbling thought is wasted on all the egocentric who seek to make a name for themselves in history. Everyone should seek to have God blot out their sins instead (Acts 3:19)!
He shall judge the world in righteousness” (vs. 8) is the very description of Jesus Christ in the final Judgment (Acts 17:30-31). Hence Psalm 9 easily describes the ultimate Judgment of all mankind, which has been committed into the hands of Jesus that all should honor Jesus as the Christ, the Son of the living God (John 5:22-23). God is righteous in condemning the wicked, for “The nations have sunk down in the pit which they made” (vs. 15). Damnation is of one’s own choosing!