In 9mm, you will find a lot of combinations will work just fine in both pistols and carbines. Thats what ive found.
Now, with slower powders (slow for 9mm) and heavier bullets you can make some superb loadings for the carbine that probably wouldnt be ideal out of the 26. For example Blue Dot, Longshot, or AA#7 with 147 grain bullets.
YES you can make different loadings to be optimized for each, especially since your barrel lengths are so different. Were talking if you want OPTIMAL performance.
I have a 10mm Glock 40 MOS and a CMMG Banshee and ive developed loads for both, mostly because the Banshee has a fully unsupported chamber, and the upper end loads, the brass comes out looking like a mushroom. Although CMMG says its not a problem, nor is it unsafe....but i sure dont like it. They say that UZIs do the same thing, and have a huge unsupported area of the chamber.
You might find that your 9mm carbine may not be able to take as high of pressure rounds as your pistol, based on diminishing returns of velocity, and pressure signs, etc. Enjoy, its fun developing loads custom made for certain weapons.