Yes, the INSCYD test is only directly available to coaches (and institutions),
but there are several coaching services that offer the test.

The test is available for any sport as long as you can provide speed/lactate
or power/lactate data. So, it would work for running since you know the
pace when you do the test.

It wouldn't work for cross-country skiing (something I am also
interested in), because you can't have speed data (unless you
do a test on a treadmill with roller-skis).