My glove size is 9. What size of gauntlets should I order if I want to wear padded leather gloves inside?

If you want to wear un-padded leather gloves in the gauntlets, order both in the same size (in your case size 9). With padded leather gloves we recommend to order the gauntlets always one size higher (so in your case 10). If you discover that the goods do not fit after receiving it, you can exchange it for free. You only pay the shipping costs.