I9, i9 or I-9 may refer to:
Science and technology Intel Core i9, a line of high-performance processors Gulftown, microprocessors originally rumored to be called the Intel Core i9 Inline-nine engine, a straight engine with nine cylinders ICD-9, a coding system for medical diagnoses and procedures
Other uses Form I-9, a US Citizenship and Immigration Services form Air Italy (2005–2018) (former IATA code: I9), a former Italian airline Interstate 9, a proposed upgrade to California State Route 99 Skaraborg Regiment (infantry) (designation: I 9), a Swedish Army infantry regiment disbanded in 1942 Japanese submarine I-9, an Imperial Japanese Navy submarine
See also I Nine, an American band 9I (disambiguation)