A deflected shot past goalkeeper Moses Ocheje after 28 minutes at the empty June 30 stadium settled the second leg of the semi-final after a 3-3 draw in Nigeria two weeks ago.
Record six-time African champions Ahly advanced 4-3 overall and face bitter rivals and title holders Esperance of Tunisia over two legs during November, with the Egyptians having home advantage first.
Geddo, who became the five-goal star of the 2010 Africa Cup of Nations after entering the tournament as an unknown, had scored only once in the Champions League this season before the semi-finals.
But a first-leg brace followed by the second-leg winner lifts him to four goals, two less than leading Ahly scorer Mohamed Aboutrika, who is serving a two-month club suspension for refusing to play in a recent game.
Geddo could have finished the return match with four goals as the woodwork denied him twice in the opening half and once after the break while Sunshine substitute Harrison Egbune rattled the crossbar in the latter stages.
Ahly controlled most of a match that rarely rose above the ordinary and was played behind closed doors with Egyptian authorities refusing to allow spectators amid post-Arab spring security fears.
Competing in the Champions League for the first time this season, Sunshine seemed overawed apart from a brief second-half spell when Tamen Medrano, Dele Olorundare and Egbune threatened goalkeeper Sherif Ekrami.
There was pre-match drama as a group protesting the refusal of the government to lift a nine-month ban on domestic football tried to prevent Sunshine leaving their hotel.
Ahly suppporters reportedly rushed to the hotel in a Cairo suburb and ensured Sunshine could travel to the Air Defence sports village where the match venue was situated.
Had the Nigerian team been prevented from playing, Ahly could have faced expulsion from the premier Pan-African club football competition, which turns 50 in two years.
No domestic fixtures -- apart from a Super Cup game in Alexandria -- have been played since 74 people died in post-match rioting after Ahly lost to Al Masry in Port Said last February.
Ahly have played six home fixtures en route to the Champions League final without any support while fellow Cairo club Zamalek were permitted 3,000 spectators at one of six fixtures, with the rest staged behind closed doors.
Esperance booked a third consecutive final appearance after overcoming TP Mazembe from the Democratic Republic of Congo 1-0 at home Saturday following a goalless first encounter.
Defender Mohamed Ben Mansour snatched the winner 20 minutes from time, sneaking in at the far post to steer a deflected free kick past goalkeeper Muteba Kidiaba.