Involved in abscisic acid (ABA) signaling during seed germination and abiotic stress response. Acts as positive regulator of ABA-mediated inhibition of seed germination, and tolerance to drought and cold stresses (PubMed:26362328). Inhibits the activity of the protein phosphatases PP2C06 and PP2C09 when activated by abscisic acid (ABA) (PubMed:24743650). Homodimer. Interacts with PP2C06 (PubMed:24743650). Interacts with PP2C50. Binding to PP2C50 is dependent on the presence of abscisic acid (ABA) (PubMed:28827170). Interacts with PP2C30 and PP2C53. Binding to PP2C30 and PP2C53 is dependent on the presence of ABA (PubMed:26362328). Repressed by abscisic acid (ABA). Plants overexpressing PYL9 exhibit abscisic acid (ABA) hypersensitive phenotype during seed germination. Plants overexpressing PYL9 exhibit tolerance to cold and drought stresses. Belongs to the PYR/PYL/RCAR abscisic acid intracellular receptor family.