Has a 11,12(11',12') 9-cis epoxycarotenoid cleavage activity. Catalyzes the first step of abscisic-acid (ABA) biosynthesis from carotenoids. a 9-cis-epoxycarotenoid + O2 = 2-cis,4-trans-xanthoxin + a 12'-apo-carotenal 9-cis-violaxanthin + O2 = (3S,5R,6S)-5,6-epoxy-3-hydroxy-5,6-dihydro-12'-apo-beta-caroten-12'-al + 2-cis,4-trans-xanthoxin 9'-cis-neoxanthin + O2 = (3S,5R,6R)-3,5-dihydroxy-6,7-didehydro-5,6-dihydro-12'-apo-beta-caroten-12'-al + 2-cis,4-trans-xanthoxin Binds 1 Fe(2+) ion per subunit. Plant hormone biosynthesis; abscisate biosynthesis. Partially bound to the thylakoid. Expressed in flowers (PubMed:29632966). Expressed in developing and ripening fruits (PubMed:22345638, PubMed:22108525). Expressed in the meristem during gametogenesis and mainly in ovule, stigma, anther/pollen and vascular tissues during flower development. In flower buds, present in petal primordium and apical meristem. Later expressed in stamen primordium and pistil meristem after petal formation. Accumulates in stamen, pistil and vascular tissues of the bud base. Highly expressed in sporogenous cells in anther, pistil stigma, ovules, pollen grains, anther walls, and basal vascular bundle. In anthers, first present at high levels, then declines rapidly from stage 13 (when microspores transform into vacuolated pollen grains after mitotic divisions) to stage 16 (when the sepals are better separated, and the faint yellow petals are clearer) to a very low level (PubMed:29632966). In fruits, expressed at high levels at the immature stage and then declined continually through all stages of fruit development (PubMed:22345638, PubMed:22108525, PubMed:25039074). Induced by abscisic-acid (ABA) and dehydration. Belongs to the carotenoid oxygenase family.