The UCC itself adheres to all of the classic Christian creeds (Apostles, Nicene, etc.) There is, however, a lot of diversity in the UCC - so, from congregation to congregation, person to person, you would encounter diversity across the theological spectrum.
As for me personally...
I believe that Jesus is the Christ, the Jewish Messiah, who was conceived by the virgin Mary, is the incarnation of God, is 100% divine and 100% human, lived a perfect and sinless life, showed us how to enter the Kingdom of God... was crucified for all of our sins, died, was buried, rose again on the 3rd day in bodily form, ascended into heaven, was vindicated by God...
Jesus serves as our priest, between us and God... the temple veil is torn and all can encounter God...
someday Jesus will return again and the Kingdom of God will exist on earth, forever.
Not all UCCers would agree with my statement, but I speak for myself.