"Give me suggestions on how to replace belt on 99 tracker.  Tensioner pulley does not seem to be working properly when wrench is applied"

Only thing I can suggest is that you rotate the pulley bolt and not the bracket bolt. I made this mistake once. Got the belt off, but then had a real problem getting the belt back on same way I took it off. DOH!!!

Use a breaker bar with proper size socket and rotate it opposite of the belt. This should work.