Some additional comment to Connor's anwer.
RPAD means padding (spaces, by default) to the right. Your requirement to keep the number right justified suggests to use LPAD.
Decimals separators can be a dot or a comma depending on nls settings. You can denote a decimal separator while converting a number to a character by using a 'D'.
The input might be between -1/2 and 1/2: I guess you want a leading zero in that case. That's why you would need to denote a '0' before the decimal separator in the conversion format string.
Finally, if you meant to output max nine characters
, then you might need
LPAD (TO_CHAR (NUM_FIELD, '999990D00'), 9)