Both are the same size and a “Fit List” is on the product page for each product.
Here it is for quick reference:

380ACP

  • Pico Berretta
  • Diamondback DB380
  • Kel-Tec P-3AT
  • Ruger LCP
  • Seecamp 32
  • North American Arms Guardian .380 & .32
  • Smith & Wesson Bodyguard
  • Taurus 738 TCO .380 (Various Models)

9MM

  • Springfield Armory XDS 9mm, .40 & .45
  • Glock MOD 43 & 42
  • Smith & Wesson 9MM & .40
  • Ruger LC9
  • Khar Arms CM9
  • Kel-Tec PF-9 9MM