Involved in ciliogenesis (PubMed:32453716). It is required for appropriate acetylation and polyglutamylation of ciliary microtubules, and regulation of cilium length (PubMed:32453716). Acts as a positive regulator of hedgehog (Hh)signaling (By similarity). May participate in the trafficking and/or retention of GLI2 and GLI3 proteins at the ciliary tip (By similarity). {ECO:0000250|UniProtKB:E7F187, ECO:0000250|UniProtKB:Q9D2I5, ECO:0000269|PubMed:32453716}. This is the function of ARMC9 (armadillo repeat containing 9, Ensembl gene identifier ENSG00000135931).