It should be noted that first of all, Caedmon is a saint in the Roman Catholic church. St. Caedmon is also not just an Anglo Saxon poet but THE earliest English poet whose name is known. A soft "a" is how it is supposed to be pronounced, however everyone I have met with the name uses a hard "A". This may be because of how it is spelled or because of the band "Caedmon's Call" which pronounces it that way as well.