Teenage winner Kennedy and defender Pennington had both extended their stays at Prenton Park earlier in the month but will now go back to Goodison Park ahead of schedule.
Pennington made nine appearances while Kennedy turned out for Rovers on eight occasions.
"Kennedy and Pennington have been recalled to strengthen their development squad," assistant manager John McMahon, filling in for Ronnie Moore following his suspension, said.
"It is a blow because they're two very good lads and two very good players.
"It's up to us to fill those voids, whether it's in house or looking at something else, it is up us as a club and a staff to decide.
"But a big thank you to the two kids who have been fantastic around the place, it's a credit to the way they've been brought up."