The function of SLC26A9 (solute carrier family 26 member 9, ENSG00000174502) is as follows. Ion transporter that can act both as an ion channel and anion exchanger (PubMed:15800055, PubMed:17673510, PubMed:26801567, PubMed:32818062). Mainly acts as a chloride channel, which mediate uncoupled chloride anion transport in an alternate-access mechanism where a saturable binding site is alternately exposed to either one or the other side of the membrane (PubMed:17673510, PubMed:26801567, PubMed:32818062). Also acts as a DIDS- and thiosulfate- sensitive anion exchanger the exchange of chloride for bicarbonate ions across the cell membrane (PubMed:11834742, PubMed:15800055). {ECO:0000269|PubMed:11834742, ECO:0000269|PubMed:15800055, ECO:0000269|PubMed:17673510, ECO:0000269|PubMed:26801567, ECO:0000269|PubMed:32818062}.