12521 ÷ 9 = 1391 R2
Alright, let's work through the division of 12521 by 9 step by step.

Step 1:
9 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 1 to get 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 9

Step 2:
9 goes into 12 1 times with a remainder of 3.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 9 from 12 to get 3.
Bring next digit (5) of the dividend behind the 3 and repeat the process: 35 / 9

Step 3:
9 goes into 35 3 times with a remainder of 8.
Write down 3 as next digit of of the result. 
Result so far: 13
Subtract 27 from 35 to get 8.
Bring next digit (2) of the dividend behind the 8 and repeat the process: 82 / 9

Step 4:
9 goes into 82 9 times with a remainder of 1.
Write down 9 as next digit of of the result. 
Result so far: 139
Subtract 81 from 82 to get 1.
Bring next digit (1) of the dividend behind the 1 and repeat the process: 11 / 9

Step 5:
9 goes into 11 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 1391
Subtract 9 from 11 to get 2.

The final result is 1391 with a remainder of 2.