It was a Monday.
August 9th, 1979 fell on a Thursday.
The 9th of August can occur on any day of the week. As the question was asked in July 2014, it is possible you were referring to August of 2014, in which case the answer is Saturday.
August 16 1954 was a Monday.
August 7, 1954 was on a Saturday.
August 14th 1954 was a Saturday.
August 18th 1954 was a Wednesday.
August 25, 1954, was a Wednesday.
August 30 1954 was a Monday.
6th August 1954 was a Friday.
Thursday
its on a Monday!
Tuesday