The subordinate conjunction that is extant in 𝓞 but missing in 𝓟; nonetheless, the 1830 edition has the that, most probably because for this section of the text the 1830 edition was proofed against 𝓞, not 𝓟 (see the general discussion under Alma 42:31). For more on the textual preservation of minor words in this part of the text, see the nearby discussion under Alma 44:8 regarding had. Also see the discussion under Alma 19:9 regarding the occurrence of the subordinate conjunction that after the verb believe.
Summary: Maintain in Alma 44:9 the subordinate conjunction that after believe, the reading in 𝓞 (“but we believe that it is your cunning that hath preserved you”).