Interpreting the question as [kglr](https://mathematica.stackexchange.com/users/125/kglr) has [done](http://mathematica.stackexchange.com/a/113929/106), and using listA and listB as given in [kglr](https://mathematica.stackexchange.com/users/125/kglr)'s [answer](http://mathematica.stackexchange.com/a/113929/106):

    Cases[listA, {#, x_} :> Sequence[#, x]] & /@ listB /. {} -> Null

>{Null, {10, 0.239651}, {1, 0.00869692}, {9, 0.181763}, 

>{9, 0.181763}, Null, Null, {6, 0.074256}, {3, 0.0413228}, Null}

Or

    Cases[listA, {#, x_} :> Sequence[#, x]] & /@ listB /. {} -> Nothing

> {{10, 0.239651}, {1, 0.00869692}, {9, 0.181763}, {9, 0.181763}, 

> {6, 0.074256}, {3, 0.0413228}}