N.M.
Maybe he's overtired when throws his tantrums. If he's not taking a nap in the morning then maybe he still needs one or some quiet time alone. Also, he may need more sleep at night. You might try putting him to bed 30 min earlier than usual and see if it helps. Don't worry that he'll wake up earlier, he probably won't. I've read this suggestion in several books and articles while searching for answers with my own children. About the crawling, I wouldn't make a big deal out of it. My two-year old goes through phases where she wants to crawl like her little brother. It's just a different way of getting around. As long as he still walks too, I'd let him be. Good luck.