The deals include the purchase of F-16 fighter planes and the extension of a defense cooperation agreement between the countries for 15 years.
Trump had said during a brief media availability before Thursday's meeting that Bahrain is "doing a lot of business" with the U.S. and "buying a lot of things." He cited the $9 billion figure.
Crown Prince Salman bin Hamad Al Khalifa says the visit was important to the kingdom and the 100-year relationship between the two countries.
He says the U.S. and Bahrain will continue to strengthen ties that the people of both countries have benefited from.
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