Here the 1841 British edition added the of to “the land Bountiful”; the following 1849 LDS edition removed it. As noted under 1 Nephi 17:7, either reading is possible, although most instances in the text lack the of. In each case, the critical text will follow the earliest extant reading, in this case “the land Bountiful” (the reading in 𝓟). 𝓞 is not extant here, but spacing between extant fragments of 𝓞 suggests that the of was not in 𝓞.
Summary: Maintain in Alma 52:9 the earliest extant reading without the of in “the land Bountiful” (the reading in 𝓟).