Involved in brassinosteroid (BR) biosynthesis (PubMed:15703058, PubMed:17138693). May convert teasterone (TE) to 3-dehydroteasterone (3DT, 3-DHT), or 6-deoxoteasterone (6-deoxoTE) to 3-dehydro-6-deoxoteasterone (6-deoxo3DT, 6-deoxo3DHT) (PubMed:15703058). C-23 hydroxylase that converts directly (22S,24R)-22-hydroxy-5-alpha-ergostan-3-one and 3-epi-6-deoxocathasterone to 3-dehydro-6-deoxoteasterone (6-deoxo3DT, 6-deoxo3DHT) and 6-deoxotyphasterol (6-deoxoTY), respectively (PubMed:17138693). These C-23 hydroxylation shortcuts bypass campestanol, 6-deoxocathasterone, and 6-deoxoteasterone (6-deoxoTE) (PubMed:17138693). Catalyzes also the conversion of cathasterone to teasterone (TE), 6-deoxotyphasterol (6-deoxoTY) to 6-deoxocathasterone (6-deoxoCT), (22S,24R)-22-hydroxyergost-4-en-3-one (22-OH-4-en-3-one) to (22R,23R)-22,23-dihydroxy-campest-4-en-3-one (22,23-diOH-4-en-3-one) and (22S)-22-hydroxycampesterol (22-OHCR) to (22R,23R)-22,23-dihydroxycampesterol (22,23-diOHCR) (PubMed:17138693). 3-epi-6-deoxocathasterone + O2 + reduced [NADPH--hemoprotein reductase] = 6-deoxotyphasterol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] (22S,24R)-22-hydroxy-5alpha-ergostan-3-one + O2 + reduced [NADPH--hemoprotein reductase] = 3-dehydro-6-deoxoteasterone + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] kcat is 0.12 min(-1) for (22S)-22-hydroxycampesterol (PubMed:17138693). kcat is 1.27 min(-1) for (22S,24R)-22-hydroxy-5-alpha-ergostan-3-one (PubMed:17138693). kcat is 1.01 min(-1) for (22S,24R)-22-hydroxyergost-4-en-3-one (PubMed:17138693). kcat is 1.10 min(-1) for 3-epi-6-deoxocathasterone (PubMed:17138693). kcat is 0.29 min(-1) for 6-deoxocathasterone (PubMed:17138693). Plant hormone biosynthesis; brassinosteroid biosynthesis. Expressed in leaf vascular tissue. No visible phenotype under normal growth conditions, but the double mutant plants cyp90c1 and cyp90d1 exhibit a characteristic brassinosteroid-deficient dwarf phenotype. Belongs to the cytochrome P450 family.