Update:My son talk to two different people at his community college on the question
I posted above, and he got two different answers unfortunately.
One person said he had to take Oral Communication class to get IGETC certified,
and the other person said he will get IGETC for UC without Oral Communication class
as UCs do not require it.
He will just take the class just in case as he needs one more class to stay
as a full time student for UC Davis TAG.
They also gave him two different registration dates for spring semester.
Not very helpful at all…