It does seem weird to not take 'stuff' w/ you to the AOG B&B for I-day, but you won't need it
my son took: (carried in a backpack)
disposable toothbrush, disposable razor, clothes to sleep in, clothes for I-day (same clothes he wore on the plane), required USAFA paperwork (incl.ID's, passport)
also,if it applies:
glasses, contacts, orthodontic retainer, medications, ABU boots if you have them, cell phone? His B&B host let him call us when he got there b/c he left his phone home and we sent it out to him when he could have it, so it wouldn't get lost
2 days before he left, his buddies shaved his head so he didn't need a comb
he still got a hair 'touch up' on I -day according to regs.
I know, it seems very weird, but look at the issue list they give you (he did want more U-wear after BCT b/c the few they give you get trashed beyond recognition)
good luck!!