Homeboys, who also forced a scoreless draw against Sharks in July, made sure that they picked four points from the league's newcomers.
The Westerners beat the Nairobi-based side 2-1 in a Kenyan Premier League match staged at the Mumias Complex on Saturday.
Opondo gave the host the lead in the 24th minute but Kariobangi Sharks shelved the lead through Masoud Juma from a deadly counter attack.
Wanjala headed home the winner from a Ali Bhai free-kick to hand Kakamega Homeboyz the three vital points that pushed them to seventh position on same points as Sharks.
Sharks, who lost their last league match to Zoo Kericho last Wednesday, are six, just a place above Homeboyz with both sides having 29 points from 19 games.