This question is similar to this one asked before ( https://mathworks.com/matlabcentral/answers/402080-how-to-find-the-neighbors-of-each-element-in-a-matrix#answer_321522)
So if I understand it corect you want something like this
%small 5x5 example matrix
A = [0 1 0 0 0;
1 1 0 0 0;
0 0 1 1 1;
0 0 1 0 1;
0 0 1 1 1];
%create matrix with zeros with size of A
M = zeros(size(A));
%use the coordinates from ginput; M(row,col)
M(1,1) = 1;
%convolution
C = conv2(M,[1,1,1;1,0,1;1,1,1],'same')>0;
%return indices
[row col] = find(C>0);
%return values (which in your case isnt really interesting cuz will only returns 1's)
A(C)
