Sydney led at halftime with a goal from defender Sebastian Ryall and sealed their win with further goals from midfielder Milos Dimitrijevic and Ibini.
The Sky Blues will face Melbourne City or last year's FFA Cup winners Melbourne Victory in the final on November 29, with the duo set to clash in the second semi-final on October 25.
As has been the case in a number of games this season it was the underdog who started the match as the aggressor, with Canberra Olympic's Philippe Bernabo-Madrid having the first attempt on goal with a spectacular bicycle kick sailing over the crossbar.
Bernabo-Madrid came close again in the 15th minute, only just failing to get any contact on a well placed cross into the box.
However it was Sydney who opened the scoring, with Ryall converting on a Rhyan Grant cross in the 22nd minute, heading the ball past Olympic keeper Angelo Konstantinou.
Bobo came close ten minutes later after latching on to a Grant chip, but Konstantinou was up to the task while Alex Brosque had an open header rebound off the post five minutes before the break.
Canberra manager Frank Cachia undoubtedly had some inspirational half-time words for his side, as they again came out on the attack after being on the back-heel for the remaining 20 minutes of the first half with Bernabo-Madrid involved once more.
However it was Sydney who would score the second, with Dimitrijevic curling a beautiful free kick past Konstantinou to put the A-League club up 2-0 in the 65th minute.
In further good news for Sky Blues fans Ibini made his return to the pitch for the first time in a competitive match since the 2015 A-League grand final, playing the final 20 minutes of the match as he came on for Filip Holosko.
Celebrations with @TheCove23 post match! We're through to the final!! #SydneyIsSkyBlue #COLvSYD pic.twitter.com/W0caJEHSxf — Sydney FC (@SydneyFC) October 19, 2016
The winger looked as if his health troubles were well and truly behind him, chasing down a Matt Simon cross to power the ball into the back of the net in the 82nd minute to cap off his first match in 18 months.
Olympic had the opportunity to get one back in the 88th minute after receiving an indirect free kick from just six yards out but were unable to capitalise, with Sydney's wall holding fast as they saw out the game 3-0.
