The verb translated as give thanks is also translated as thank in Psalm 7:17. This shows a strong connection between Psalms 7 and 9 (see 7:17; 8:1–2).
The phrase with all my heart shows the psalmist’s deep devotion and commitment (Psalms 86:12; 111:1; 119:10; 138:1).
I will recount: These stories teach the next generation (Psalms 78:4; 145:4). If forgotten, a generation might easily turn away from the Lord (Psalms 78:11, 32).
Your wonders: These include the Lord’s judgments on the enemies of his people (Psalm 9:4) and his care for the oppressed (9:9). The wonders in creation, redemption, and revelation show his character and power (Psalms 89:5; 111:4; 119:18, 27). His powerful acts inspire public praise (Psalm 9:1; 26:7; 75:1).