#MathGolf , (削除) 6 (削除ここまで) 5 bytes

9{îÄí

-1 byte thanks to @maxb.

Try it online.

Explanation:

9{ # Loop 9 times:
 î # Push the 1-based loop index
 Ä # Do an inner loop that many times, using a single command:
 í # Push the total number iterations of the outer loop
 # (after the loops, the entire stack is joined together and output implicitly)

MathGolf , (削除) 6 (削除ここまで) 5 bytes

9{îÄí

-1 byte thanks to @maxb.

Try it online.

Explanation:

9{ # Loop 9 times:
 î # Push the 1-based loop index
 Ä # Do an inner loop that many times, using a single command:
 í # Push the total number iterations of the outer loop
 # (after the loops, the entire stack is joined together and output implicitly)

#MathGolf, 6 bytes

9{î░î*

Try it online.

Explanation:

9{ # Loop 9 times:
 î # Push the 1-based loop index
 ░ # Convert it to a string
 î # Push the 1-based loop index again
 * # And repeat the string that many times
 # (after the loop, the entire stack is joined together and output implicitly)

#MathGolf, (削除) 6 (削除ここまで) 5 bytes

9{îÄí

-1 byte thanks to @maxb.

Try it online.

Explanation:

9{ # Loop 9 times:
 î # Push the 1-based loop index
 Ä # Do an inner loop that many times, using a single command:
 í # Push the total number iterations of the outer loop
 # (after the loops, the entire stack is joined together and output implicitly)