creating wallpapaer

Yes and no. As with so many other projects, it depends on how you plan to actually produce/print the result. As nearly all printing processes, including large-format and "grand format" output, can work from scaled document sizes, you are really only limited by what a print provider can handle.

One "no" is that InDesign has a hard document size limit of 216 inches (in either dimension). So at a minimum, you'd need to work to about 4:1 size — a 216 inch document could be printed 400% size for exactly that 864 inch length. A secondary "no" is that PDF, which you would almost certainly need to export the document to for print handling, has a limit of 200 inches, so you'd really have to work at a 5:1 ratio.

Neither of which is a hard limit; using vector graphics, scaling is infinite, and for any raster/image components, it's fairly simple to use high-resolution imaging that will scale up to no more than the practical limit of 300dpi. (That is, you would use 1200 or 1500ppi images for the 4:1 or 5:1 upscaling.)

This all assumes you need 864 unique inches, which is rare in wallpaper. You could use a repeating pattern of a full 54 inches by... 10 inches? 24 inches? 96 inches? or up to 200 inches. It would be up to the printer to replicate the pattern for the full length. (You could also simply break up a unique layout into 4, 5 or more "pages" and again let the printer do the imposition and seaming.)

But again, it all is a matter of working backwards from the printer/print technology/output limitations to a correctly sized source document, and with scaling, ID can handle almost any size even jumbo-format, mega-billboard output can produce.

There is no reason I can think of you'd need a design app to handle that full 800+ inches in linear, 1:1 format as long as the overall process allows such scaling.

One hint: I have always found it useful to work to one pica == one inch or a 6:1 ratio, as the numbers map exactly with no fancy math to mess up.