The address of the chapter as appears in Psalm 9:1, talks about the death / defeat of the wicked.

Song 9 opens in a mood of jubilation. The verbs of joy surge: “acclaim” and “tell” of v. 2 build to “rejoice and  exult” and “sing” of v. 3. The exultation ebbs away as the singer –certainly he is David, so identified in v. 1, but, even more so, as he makes clear he is king over, and thereby judge of, his people– gives the reason for his acclamation: his belief that God approves of and agrees with his judgements and rulings. His proof  –that his enemies have not merely been defeated but, indeed, annihilated. The joy of verses 2 and 3 echoes in v. 12 as the singer tells his people to “sing a hymn to Adonai”. But though he proclaims that God will be merciful to the “lowly” (v. 13), to the “needy” and the “poor” (v. 19), he makes God’s mercy a condition of his exultation: his plea, “Have mercy on me”, in v.14, is followed, in v. 15, by “so that I might tell to all Your praise”.  Not until v. 20 does his jubilation ring out, with even more power than in the opening verses. His “Arise, Adonai” sounds a final chord of both triumph and rejoicing.

Perhaps because David, the King and Judge of Israel, describes himself as counselled and defended by God, the Ruler and Judge of all creation, his praisesong is structured –at least its first half– upon pairings:
–of verbs:     v. 2 : “acclaim” and “tell of”
v. 3: “rejoice” and “exult”
v. 4: “stumble” and “perish”
–of nouns:    v. 5: “judgement” and “adjudication”
–of adverbs: v. 6: “forever” and “eternally”
In echo of v. 5, v.9 pairs the verbs “judge” and “adjudicate”. (V. 7 offers a variation, a triplet of verbs: “gone”, “tear down”, “perish”.)
V. 10, twice repeating the noun “fortress”, prepares the structure of the second half of the praisesong:  although verses 11 to 21 do not repeat specific words, still, of the two statements making up each verse, the second simply re-iterates the first. (That there are three-parts to v.17 and v. 20 does not contradict this pattern, for each of these verses begins with a declaration that is followed by two descriptions of that declaration.)

David’s perception of the correspondence between his role as King and Judge of Israel and God’s role in creation, is described in the praisesong by two metaphors. Seemingly disparate, these two metaphors come together, by the song’s end, to form a symmetrical whole. The first metaphor gives the identifier, “Name”, to God and it is that aspect of God which David dedicates his song to: thus v. 3 declares “I will sing a hymn to Your name, O most High” (not, that is, to God directly, but, rather, to God’s name).* V. 11 continues the metaphor  –“so let those who know Your name trust You’–  and, accordingly, his own trust in God thus assured, David is then able in v. 11 to sing his praisesong not to God’s name but to God. In terrifying contrast are the wicked, trapped and destroyed by their own perfidy (v. 16 describes them as caught by one foot in the trap of their own devising, an image as suggestive of their savagery –for so is a wild beast netted– as much as it is of their self-defeat); they are condemned by God to perish, but, even more so, their very names are to be obliterated, struck from human memory, their lives –past, present and possibility of future– thereby wiped from time:
v. 6: “You blast the nations; You cause the wicked to perish; You blot out their name forever, eternally.”
Verse 7 adds, “their very recollection has perished.”
The hymn David sings declares that those who seek God seek the name that rules, judges, forgives and protects them: v. 11: “so let those who know Your name trust You, for You do not abandon those who seek You, Adonai.”
In bleak contrast, the wicked, their very names obliterated, are, in their very essence, unnamed, and, thereby, uncreated.

Just as the first metaphor describes David’s perception of God, so his second metaphor expresses his relationship –in fact, all of creation’s relationship– with God. The metaphor is one of placement, it locates, throughout the song, the exact space occupied by God. Thus it imagines a kind of map, placing God closer and closer to earth and its inhabitants. The perception is not of God as possessing a material form, a mass, rather it implicitly places the responsibility on humankind, which, depending on its worthiness, can conceive of God as drawing closer or further from it. Thus, in v. 5, God, upholding King David’s judgements and rulings, stays “on the throne as righteous judge” — the image is of God enthroned in a court of judgement, high above the human sphere. V. 8 re-iterates: “But Adonai shall stay forever; he has set up His throne for judgement”. The image of God in v. 10 as “a fortress for the oppressed, a fortress in times of trouble”, brings God closer, as the unshakeable haven for those who need protection. Verse 12 places God “in Zion”, dwelling among those who proclaim “His deeds among the peoples”. No longer enthroned in the heavens but now dwelling among the righteous, God, in David’s image, is, in v. 14, a benefactor. Not a stone barricade, but a giver of succor: “You who lift me from the gates of death”. This perception of God leads to the singer’s affirmation in v. 17, “Adonai is well known”, known by both works and judgments (“He works judgement”). The final spatial metaphor, in v. 20, is in the form of the singer’s exhortation to God, in his exultant “Arise”.

It is the exultant cry, “Arise”, that binds together the two metaphors: one of name. one of location. Both, descriptions of God, the indescribable. The singer is therefore able to assert that God is “well known”; certainly God is “known” to the singer by means of his metaphors. For they both identify and locate the One whom he triumphantly calls upon to fill the earth and the heavens: “Arise”.

After such peals of sound, the song abates. Its final chord is more poignant than it is admonitory: “let the nations know they are but men” (v. 21).

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*Because God’s essence is unknowable, any descriptive word or epithet, be it noun or adjective, given to God, is, accordingly, a metaphor. A way He refers to us in a specific time, place ad circumstance.