There is some evidence that Oliver Cowdery tended to repeat the determiner their in conjunctive structures involving a conjoined abomination(s). Here in verse 2, Oliver initially wrote “their iniquity & their abominations” but virtually immediately crossed out the repeated their (there is no apparent change in the level of ink flow for the crossout). The 1830 reading lacks the repeated their and thus agrees with the corrected reading in 𝓟. This agreement argues that 𝓞 also lacked the their before abominations. Later in verse 7, Oliver made the same initial error in 𝓟:
In this instance, the ink for the crossout of the repeated their is somewhat heavier.
Usage elsewhere in this chapter shows that either reading, with or without the repeated their, is possible for a conjoined abominations:
So for each case, the critical text will follow the earliest sources. Thus there is a repeated their in verses 5, 10, and 12 but not in verses 2, 7, 8, and 11. Overall, there are 13 instances of the repeated their for a conjoined abomination(s) but 19 without the repeated their.
Summary: In 3 Nephi 9:2 there is no repeated their for the conjunct abominations; for each instance of a conjoined abomination(s), we follow the earliest textual sources; thus the repeated their occurs in verses 5, 10, and 12 in this chapter but is lacking in verses 2, 7, 8, and 11.