Salman But for test Cricket Salman Butt was the youngest captain of pakistan cricket team
Youngest test captain is Tatenda Taibu of Zimbabwe, when he was 20 years and 358 days.
Mohammad Ashraful scored 114 aged 17y 61days for Bangladesh v Sri Lanka on colombo in 2001
Sachin played for only one T20. He retired in 2013 from test cricket.