Since halogenation of alkanes is mostly uncontrolled, you are likely to get a mixture of mono and polysubstituted products. These will be-
Monosubstituted: 1
Disubstituted: 2
Trisubstituted: 2
Tetrasubstituted: 2
Pentasubstituted: 1
Hexasubstituted: 1
Thus, you get a total of 9 structural isomers.
Note - none of the above products will be active.