While I am of the view that it will have to be points from a credit card that has not posted before, I don't see the connection between the first part of your sentence and the last part given:
Please allow up to eight weeks after the registration period, ending 1 November 2018, for the 10,000 bonus Qantas Points to be credited to your Qantas Frequent Flyer account with the description 'Credit Card Bonus Points’.
Also as they say:
- Make an eligible purchase on your new card before 20 September to ensure that the points you’ve earned from your purchase are credited to your Qantas Frequent Flyer account before 1 November 2018
I would guess that they will not start assessing if the bonus has been earnt till 1 November.
Unfortunately I have not seen anything which would clarify if one can only earn the one 10K bonus, or whether it will be coughulative.