Select items in a list that contain criteria #2

E.g.

L = Tuples[{1, 2, 3, 4, 9}, 4];

Pick[L, Total[Clip[L, {9, 9}, {0, 0}], {2}], 18]

If you need it repeatably, you could make a list of parts

parts = Position[L, _?(Count[#, 9] == 2 &), {1}][[All, 1]];

and simply write L[[parts]]

L = Tuples[{1, 2, 3, 4, 9}, 4];

Pick[L, Total /@ UnitStep[L - 8], 2]

Or

Pick[L, Total /@ UnitBox[L - 9], 2]

list=Tuples[{1, 2, 3, 4, 9}, 4];
Cases[_?(Count[#, 9] == 2&)] @ list
Pick[list, Lookup[Counts /@ list, 9, 0] - 2, 0]

both give

{{1, 1, 9, 9}, {1, 2, 9, 9}, {1, 3, 9, 9}, {1, 4, 9, 9}, {1, 9, 1, 9}, {1, 9, 2, 9}, {1, 9, 3, 9}, {1, 9, 4, 9}, {1, 9, 9, 1}, {1, 9, 9, 2}, {1, 9, 9, 3}, {1, 9, 9, 4}, {2, 1, 9, 9}, {2, 2, 9, 9}, {2, 3, 9, 9}, {2, 4, 9, 9}, {2, 9, 1, 9}, {2, 9, 2, 9}, {2, 9, 3, 9}, {2, 9, 4, 9}, {2, 9, 9, 1}, {2, 9, 9, 2}, {2, 9, 9, 3}, {2, 9, 9, 4}, {3, 1, 9, 9}, {3, 2, 9, 9}, {3, 3, 9, 9}, {3, 4, 9, 9}, {3, 9, 1, 9}, {3, 9, 2, 9}, {3, 9, 3, 9}, {3, 9, 4, 9}, {3, 9, 9, 1}, {3, 9, 9, 2}, {3, 9, 9, 3}, {3, 9, 9, 4}, {4, 1, 9, 9}, {4, 2, 9, 9}, {4, 3, 9, 9}, {4, 4, 9, 9}, {4, 9, 1, 9}, {4, 9, 2, 9}, {4, 9, 3, 9}, {4, 9, 4, 9}, {4, 9, 9, 1}, {4, 9, 9, 2}, {4, 9, 9, 3}, {4, 9, 9, 4}, {9, 1, 1, 9}, {9, 1, 2, 9}, {9, 1, 3, 9}, {9, 1, 4, 9}, {9, 1, 9, 1}, {9, 1, 9, 2}, {9, 1, 9, 3}, {9, 1, 9, 4}, {9, 2, 1, 9}, {9, 2, 2, 9}, {9, 2, 3, 9}, {9, 2, 4, 9}, {9, 2, 9, 1}, {9, 2, 9, 2}, {9, 2, 9, 3}, {9, 2, 9, 4}, {9, 3, 1, 9}, {9, 3, 2, 9}, {9, 3, 3, 9}, {9, 3, 4, 9}, {9, 3, 9, 1}, {9, 3, 9, 2}, {9, 3, 9, 3}, {9, 3, 9, 4}, {9, 4, 1, 9}, {9, 4, 2, 9}, {9, 4, 3, 9}, {9, 4, 4, 9}, {9, 4, 9, 1}, {9, 4, 9, 2}, {9, 4, 9, 3}, {9, 4, 9, 4}, {9, 9, 1, 1}, {9, 9, 1, 2}, {9, 9, 1, 3}, {9, 9, 1, 4}, {9, 9, 2, 1}, {9, 9, 2, 2}, {9, 9, 2, 3}, {9, 9, 2, 4}, {9, 9, 3, 1}, {9, 9, 3, 2}, {9, 9, 3, 3}, {9, 9, 3, 4}, {9, 9, 4, 1}, {9, 9, 4, 2}, {9, 9, 4, 3}, {9, 9, 4, 4}}