Hand 1 - he has an ace here, I don't think he is value betting a ten here - or is he? Generally, I don't try to push people off a top pair because they don't fold and I make the most of my money by people trying to push me off a top pair.

Hand 2 - be a calling station even though his line looks like he probably has a 9. Donk bet c/c c/r looks like a 9 here. But you need a good reason to fold trips in HU play.

Hand 3 - I guess it is good even though I would never make that play. I would bet turn.

Hand 4 - I don't like it. What are you trying to represent? If you had ace high, you make a c/c, right? He knows that you know that he wouldn't bluff on this board, so if he has ace high, he is going to check. So he knows that you don't expect him to value bet river thin in that spot, unless he has a 9 and it would be very risky if you had a queen, to attempt a checkraise here. So he calls with a 9. But he probably folds a T.

I don't do those c/r river a lot. I guess I should do them more often. But usually those c/r river bluffs are spews and they get called a lot. No one believes you that you would risk that villain checks behind. So people call them. Generally, don't try to push people off a top pair or a strong hand. C/r is more appropriate as a way to get paid off, not as a way to bluff.