Consequences and justice.
v.9 A quarrelsome wife. It is far better to live in a tiny corner of the attic than in a large, beautiful home with a quarrelsome wife (25:24). See v.19 below for a variation on this idea.
v.10 No mercy. The (desire of the) wicked man craves after only evil (4:16), his (needy) neighbor will see no mercy from him. Evil people are “addicted” to evil and let no one stand in the way of fulfilling their evil desires.
v.11 Punishment. The simpleminded learn by seeing the mocker punished (the mocker doesn’t learn). The wise become even wiser when they receive a rebuke (instruction). See 19:25. The wise person never stops learning, but the mocker never learns (but should be punished anyway so the simple will learn by example).
v.12 Judgment is certain. The Righteous One watches the home (or heart) of the wicked and will bring him to ruin. God sees what the wicked do in the privacy of their homes and will punish them. The “Righteous One” could alternatively be understood as a righteous man with insight (perhaps a judge).
v.13 Cry of the poor. Whoever closes his ears to the cry of the poor and needy will also call out and not be heard (poetic justice). Illustrated by the story of the rich man and Lazarus in Lk 16:19-31. Be sensitive to the needs of the poor in your area.
v.14 A bribe. A secret gift (bribe) pacifies the wrath of an angry person (as in 17:8). This is an observation, not a recommendation to offer a bribe (which was prohibited by the law). Read in connection with the previous verse, the wicked will not give to the poor but will offer a bribe to pervert justice.
v.15 Justice. When justice is done, the righteous are joyful but the wicked are terrified. This is because God is just and the wicked will get the punishment they deserve in the end (10:29). Similar to the idea in Rom 13:3.
v.16 Lack of sense. The one who wanders away from good sense (away from the way of wisdom and knowledge) will end up with the company of the dead. Illustrated by the one falls in with the adulteress (2:16-19).
v.17 Poverty. Whoever loves pleasure, wine and oil will be a poor man. E.g. 23:19-21. From a practical standpoint, if you love luxury and wine you will not be saving for your future and may end up in poverty (irony).
v.18 Ransom. The wicked and traitors serve as ransom for the upright. The idea may be that the wicked receive punishment in place of the righteous or perhaps that they fall into traps they set for others.
v.19 Quarrelsome woman. Better to live (alone) in a desert than live in a home with a quarrelsome, complaining wife. Compare v.9 above.

Read Proverbs 21:9-19