Koheles is not Proverbs (Mishlei) but Ecclesiastes and I like 9-12 better which explains it clearer and where does it say it refers to Tisha B’av and 9-11 was not Tisha B’av but Selichos. It is an issur to make any references from goyishe months and it was not 9-11 but 13 days after it as Pope Gregory removed 13 says discussed below, so we start Vesain Tal Umotor, Dec 4th or 5th rather than 60 days after the tekufa.
The reason we must adjust the Tekufas Tishri by 13 days because Pope Gregory in 1582 created a Gregorian calendar over Julian Caesar’s calendar because he adjusted the calendar by 10 days. The other days difference had to do wiith a leap year for a complete century. This should be a leap year since years divisible by 4 should be a leap year. The complete century is a hundred years. He changed it that only if is divisible by 400 will be a leap year. The years 1600 and 2000 were ok; The years 1700, 1800 and 1900 were not leap years any more. This makes the differende of another 3 days for a total of 13 days.