Have carried footballs lots of times - there really is no problem.
Standard football pressure is around 13psid - cabin pressure at SL is about 14.7 psi and at 8000' cabin altitude about 10psi - so there's only an extra 4-5 odd psi on a football that's designed to take 28psi (absolute).
I may have got diff and abs confused there, apologies. But it's not a big difference anyway, IMHO.
In any case, like balloons, if a football did burst it wouldn't explode outwards like a bomb - if you watch high-speed film of balloons bursting, the failure begins with a small rip or hole and the skin retracts along itself, not expanding outwards.