What this error means?
Index exceeds the number of array elements (9).
Example:
Suppose, an array example A=[2 3 4 5 6 7 8]; Here the array A length is 7. Now if you try to acess the array indices more than 7, then MATLAB reflects such error, as indices value exceeds array length.
Till j=7, there is no issue, once the iteration reaches j=8 and try to access A(8) here j=8, as A has 7 array elements only, then it shows such error. Please check in your code, such issue may arrised.