McCreary went down twice in the fight, from a body shot in round six and from hooks to the body in the ninth as Frampton sealed a unanimous decision victory with three scores of 100-88.
The victory comes despite Frampton admitting afterwards he believes he fractured his left hand once again in the second round, having injured his fist twice in his pre-fight camp.
Frampton will now be hoping for a shot at the WBO super featherweight title against reigning champion Jamel Herring, having previously held world titles at super-bantamweight and featherweight.
The 32-year-old Belfast man has also been linked with a fight against Oscar Valdez, who marked his debut in the same 130lbs division with a hard-fought stoppage win over the spirited Adam Lopez.
Valez, the former WBO featherweight champion, was floored in the second round, but battled back to halt Lopez in the seventh round.