Once carried a race horse to the German GP in Baden-Baden. Him and his mate, that is, an old nag which couldn't run a hundred yards if his life depended on it, but it was a good mate of the racer and kept him calm during the flight.
The single horse, and it's mate, was accompanied by an entourage of 10-odd staff, including the trainer, the vet, the vet's assistant, 4 grooms and 2 bodyguards. The vet gave us the briefing on the humane killer along these lines: 'That horse is worth more than the aircraft we're flying in. You will
not apply the human killer. If he kicks off, dump the cabin pressure and put him to sleep - the rest of us will go on portable oxygen'.
Bit dubious about this "nine horses" 744combi only has 7 pallet positions, unless they were carrying foals which is a little dodgy.
You can load up to 3 horses side-by-side in a 125/96 horsestall, for a total of 21 horses in a Combi.