The attacks around 140 kilometres northwest of Baghdad occurred outside a bank where soldiers and police had gathered to collect their pay. At least six solders and three police were among the dead.
Police say a suicide attacker parked an explosives-laden car outside the al-Rafidain bank. After that bomb detonated, the attacker walked among security forces and set off his explosives vest.
Tikrit is the hometown of the late Iraqi leader Saddam Hussein who was executed in 2006.
Nobody immediately claimed responsibility for the blasts, but Iraqi authorities say it carries all the hallmarks of an attack by Al-Qaeda,