Here the 1920 LDS edition replaced a nonstandard plural kindreds with the standard kindred. (We see a similar kind of editing in verse 13, where the 1920 edition changed the plural kinsfolks to the standard kinsfolk.) For a general discussion of the competition between kindreds and kindred in the text, see under Alma 10:4. There is also evidence that the 1830 typesetter was prone to change kindreds to kindred, especially in 3 Nephi (see the discussion under 3 Nephi 10:2). Here in Ether 8:17, the critical text will follow the earliest extant reading, namely, the plural kindreds (the reading in 𝓟 as well as in all the early editions).
Summary: Restore the plural form kindreds in Ether 8:17, the reading of the earliest text.