Here the 1874 RLDS edition replaced the past participle opened with the adjectival open, probably accidentally. The correct opened was restored in the 1908 RLDS edition. One possible motivation for the error is that the following shut is ambiguous and can be interpreted either as a past participle or as an adjective. The correct interpretation is obviously the verbal one—that is, here both opened and shut are past participle forms occurring in a passive construction. For another case where the past participle opened was accidentally replaced by the adjectival open, see under 3 Nephi 14:7–8.
Summary: Maintain in Ether 4:9 the original reading that states that at the Lord’s command “the heavens are opened and are shut”, a verbal action.