Here in the printer’s manuscript, Oliver Cowdery initially wrote these plates (“were it not for these plates”). Virtually immediately he caught his error, crossed out plates, and supralinearly inserted things. The original manuscript is not extant here but probably read these things since “these plates that these records do contain” doesn’t make any sense. Oliver’s initial error was undoubtedly the result of him anticipating the following these plates (“which are on these plates”).
Summary: Maintain in Alma 37:9 the corrected reading in 𝓟, “were it not for these things”.