Q: File size limit on USB

I would like to deliver a Wedding Film to a customer on an external hard drive (USB stick). The film format will be .MOV or .MP4 and will be approx 9GB in size. I don't know if the customer will be a Mac or Windows user.

So if i purchase a USB they are usually formatted for both operating systems but the file size limit is 4GB; and if I reformat the USB will i be limited to one operating system?

Help and advice please