Ideally you want the box(es) filled and capped before they cluster. When that might be is anyone's guess after the last few years.
Not a lot of difference between autumn feeding syrup or fondant if you are wanting it stored; syrup needs to be moisture reduced and fondant needs water to be collected.
Feeding thymolated syrup does avoid fermenting problems, should it not get capped.
Clearly much better if the box(es) are full - less 'vain space', so really needs to be completed shortly, but can depend on whether there are spare stores frames 'knocking around' for any last minute adjustments.
There should be no real problem with nine colonies - any smaller colonies could be transferred to nuc hives if there were a real mishap in the plans.
I moved two colonies yesterday and will likely unite them with two other colonies tomorrow. The spare stores frames went into two other adjoining colonies yesterday and any remaining frames of stores will go under the colonies for them to move up, if time - I expect there will be.
Just get the job appraised and sort out options dependent on how the weather progresses. Be flexible.