Is Hoya Kentiana the same plant (synonymous) with Hoya Wayetii?
No. We are talking about two different plants here. The main difference between the two lies in the color of the pedicel (pedicel = the small stalk that bears the flower of your plant). In the case of Hoya Kentianasm, this is a pinkish color, while in Hoya Wayetii, they are simply green.