Wrong SSB-A153-1 kit ordered, please help with next steps

I was at ssb a few weeks ago. They informed me they don’t make a 9” kit. I would imagine a pair of 10” spindles would be an easy grab, and probably less hassle than returning and getting a new kit. Getting a kit for my friends 71 valiant. I know my 67 has 10” drums and I’m just going to swap the spindles, if need be, to run the kit.