Carra was tested out of competition on August 24 and was provisionally suspended on August 31, the same day he was due to compete in the men's -56kg category at the London Paralympics.
He said he had taken green tea capsules which when examined were found to contain hydrochlorothiazide, a banned diuretic, even though the substance was not listed on the label.
"In accordance with the IPC anti-doping code, Bruno Pinheiro Carra will serve a nine-month suspension for the violation beginning on August 28, the date of notification," the IPC said in a statement.