"Aug-2019" can result from using "%b-%Y", not from "%m / %Y". Please double check with this doc: https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior
Since you need output like "8/2019", obvious choice for the year part is to use "%Y". But it's a little tricky for the month part, since python only allows zero padded numeric month output i.e. the "%m". The leading zero will occur for some months, but not all. A straight forward replace will not work here. I suggest using regex. The snippet below shows how regex can be used for removing the leading zero, if any.
import re
import datetime
d = datetime.datetime.now()
d.strftime('%m/%Y') # --> '03/2020'
re.sub('^0', '', d.strftime('%m/%Y')) # --> '3/2020'