install template on more than one device

You can install WordPress on multiple computers for sure. You can also copy the same template (if you mean a theme) to each one. But I don’t know if you can sync the two. Haven’t done this myself.

The best practice to work with template by multiple people is either use the SVN or access files by setting up the local server and access it via LAN connection(one file by one person at a time, multiple access may cause loss of the data to the file of either one).