How can I delete all of the zeroes to the right of the last 9 in each
row?

For example, here are some rows:

0000000000000000000009990000000
0000000099099000000000000000000
9999000000000000000000000000000
0000000000000000000000000099900
0000000000000099999990000000000
0900000000000000000000000000000
0000000000000000099999000000000

This is result I'm looking for:

000000000000000000000999
0000000099099
9999
00000000000000000000000000999
000000000000009999999
09
0000000000000000099999

Then, how do I find the longest row?