Here we have two minor errors in editions dating from the early 1900s. In the first case, the 1906 LDS edition omitted the definite article the before armies. Here the the was probably lost because at this point a new page in the 1906 edition begins; the previous page ends with is weak; and while the following page begins with armies. The loss of the the occurred as the 1906 compositor started to set a new page (or at least when he started a new line of type). It seems obvious here that the definite article the is missing, although one could, I suppose, interpret armies without the as referring to some unspecified “armies of the Lamanites”. In any event, this error was not transmitted to subsequent LDS editions because the 1906 edition was never used as a copytext.
The second error in this passage occurred in the 1905 LDS edition; there the preposition to was replaced by of. In this instance, the resulting error makes sense. The 1911 LDS edition followed this reading (since it was set from a copy of a later printing of the 1905 edition). The 1920 LDS edition restored the correct to to the LDS text. There is only one other instance of victim(s) in the text, and it also uses to for its prepositional complement:
The critical text will maintain the original preposition to here in Moroni 9:17.
Summary: Accept in Moroni 9:17 (and in Mosiah 1:14) the use of to to head the prepositional complement of the noun victims; also maintain the definite article before armies.