Here in Jarom 1:9, the 1902 LDS missionary edition introduced the singular father in place of the correct plural, fathers. The small plates of Nephi specifically state that both Lehi and Nephi individually received this promise from the Lord (see 1 Nephi 2:19–20 for Nephi and 2 Nephi 1:9 for Lehi; for additional citations of this promise, see the discussion under 2 Nephi 1:20). Thus the plural fathers is definitely correct. This plural usage is also supported by the same language (although negatively expressed) that Amaron wrote in the very next book in the small plates of Nephi:
Summary: Maintain the plural fathers in Jarom 1:9, the reading of the earliest textual sources; the plural reading is supported by the language in Omni 1:6 as well as by earlier references to this promise from the Lord to both Lehi and Nephi (“our fathers”).