Most of the suspects were junior enlisted sailors, although Navy officials said a lieutenant commander was also among those arrested.
The Bangor-class vessels were also considered overcrowded, cramming over 90 enlisted sailors and six officers into a vessel originally intended for a total of 40 officers and sailors.
Most of the dead and injured were enlisted African-American sailors.
Five of the nine were male chief petty officers while the other four were female junior enlisted sailors.
Captain Usher said private housing that was comparable to military housing cost roughly $1,000 a month, which is above the housing allowances for even the highest ranking enlisted sailors.
The Swallow Craft class vessels have a crew of 8 enlisted sailors and have a range 400 nm at 20 knots.
Enlisted sailors routinely qualify as level two military hydrographers, certifying their skills.
The Raj Hans Class vessels have an accommodation for a crew of 28 enlisted sailors.
It is currently part of the men's service dress uniform for junior enlisted sailors as well as the women's summer dress uniform.
It aims to recruit both enlisted sailors and prospective commissioned officers for the United States Navy.