The fine, which could see Boucher docked up to US$3,500, was punishment for his speaking out on the omission of all-rounder Jacques Kallis from South Africa's squad for the tournament in the country from Sept 11 to 24.
"He's the best all-rounder we've ever had and he's saved more games than anyone realises - and he is a far better one-day player than he is given credit for," Boucher was quoted as saying in Business Day on Aug 15.
"It is either those who have an issue with him, and have a chip on their shoulders, or those who have ulterior motives."
Boucher's comments were deemed to have contravened several clauses of CSA's code of conduct, including those dealing with bringing the game into disrepute, and he was summoned to a disciplinary hearing on Aug 17.
"Senior players have a responsibility to CSA and to cricket in general," a media statement on Friday quoted CSA disciplinary commissioner Michael Kuper as saying.
"Their responsibilities are set forth in the code and in their contracts and one is entitled to expect punctilious performance of their obligations.
"In the present case the comments to the media were calculated in their effect to embarrass CSA and to denigrate the T20 (Twenty20)."
The statement added that CSA had argued at the hearing that Boucher should be banned from playing in the tournament.
Boucher has until 1430 GMT on Saturday to file an appeal.