9. gave good heed—literally, "he weighed." The "teaching the people" seems to have been oral; the "proverbs," in writing. There must then have been auditories assembled to hear the inspired wisdom of the Preacher. See the explanation of Koheleth in the Introduction, and chapter 1 (1Ki 4:34).
that which is written, &c.—rather, (he sought) "to write down uprightly (or, 'aright') words of truth" [Holden and Weiss]. "Acceptable" means an agreeable style; "uprightly … truth," correct sentiment.