if for the 9 mark spectroscopy question i had put carboxyl accidentally instead of carbonyl but put (ketone) in brackets, is there a possibility i might still get that mark?
If you've drawn a ketone, written ketone, and spoken of carbonyl (correctly) in the justification that accompanies the table, I think there is a far argument to be made that you should be credited despite a minor mistake. However, if you've made the same mistake in the justification or if your answer (overall) comes across as reflecting uncertainty or as being mistaken, being penalised is the fair outcome.
Having said that, if the marking scheme treats the table and structures specifically and separately, then you could be out of luck.
Note, also, that giving two answers is generally discouraged. Suppose someone wrote carbonyl (aldehyde) and then drew a ketone, for example... the functional group is correct but the additional (and unrequested) compound class is incorrect. Should that be ignored? What if the answer said "aldehyde (carbonyl)," so that the second answer is the correct one?
In your case, would you credit the answer ketone alone, without the proper name of a functional group provided? I would argue against that being credited, but an earlier question incorrectly portrayed aldehydes and ketones as having different functional groups, so taking a hard line on functional groups vs. compound classes seems harsh.
So... is there a possibility of you getting the mark? Yes. Is there a possibility of you doing anything to influence the decision now? None at all. My advice is: move on.