To simplify this expression, we can use the properties of exponents:

(-6)^(-9) = 1/(-6)^9
6^(-7) = 1/6^7
6^(-7) = 1/6^7

Now we can substitute these values back into the expression and simplify:

(1/(-6)^9 1/6^7 1/6^7) / 6^(-15)
(1/(-6)^9 1/6^7 1/6^7) 6^15
(1/((-666666666)^9) (6^15)
(1/(-10,077,696^9) (1,077,696^15)
(1/-3.82472006710^68) 2.208142610^72
-4.819723141*10^-4

Therefore, the simplifed expression is approximately -4.82 * 10^-4.