Here Oliver Cowdery spelled Jarom as Joram. The three other occurrences of the name are consistently spelled as Jarom (including the first one, found in the title of the book):
Two of these correct spellings precede Jarom 1:14 in the text. Thus the spelling in 𝓟 of Joram is undoubtedly an error, a simple switching of the vowels, perhaps under the influence of the name Jordan. (It is doubtful that the considerably less familiar biblical name Joram led to this error.)
Summary: Retain the spelling Jarom since the first two spellings in 𝓟 of the name read that way (𝓞 is not extant for any of the occurrences of the name).