Is it a good idea to take whey protein isolate as a recovery drink after I do the insanity fitness program? And before bedtime?

Maybe, but.. Insanity is a vigorous exercise program that engages all major & core muscle groups, stimulates the release of glycogen stores and the rapid and efficient uptake of oxygen to fuel activity. Recovery from the demands of such a program requires some protein and also a high GI food to promote growth and replenish glycogen. Adding some fruit or dextrose will do the trick!
Yes and no. The whey protein drink is ok any time of day. The intense exercise before bed time that is not a good idea since it could significantly affect your ability to fall asleep. Even though you did not complain of insomnia, google "sleep hygiene" to get answers.