He's 2 1/2, his daytime routine changes somewhat and he's trying to drop his afternoon nap.

We try to put him to bed at 8pm each night but it doesn't always work that way.
How different is his day routine? Is he a child that prefers consistency and acts out when he is not sure what is happening? My DS1 was like this and needed to be told what was going to happen so he knew what was coming up in his day. This lasted a couple of months then he was able to go with the flow more easily. He could be unsure what his day will hold so gets frustrated because he is uncomfortable or nervous.

Suse definitely gave some very good advice which I heartily endorse.