In the rows A, B, D and I, the only examples of candidate 9 are to be found in the blue highlighted cells. We can't tell exactly at this stage where the solution 9s will be placed, but clearly they must be disposed in such a way that each of the rows A, B, D and I will have just one 9, and each of the columns 1, 2, 8 and 9 will also have just one 9. This will satisfy the candidate 9 solution requirement for the columns 1, 2, 8 and 9 and any additional candidate 9s in these columns (the ones highlighted in magenta) may be removed.