When Odysseus first meets Telemachus, he is still in his beggar's outfit. However, this is not really considered the reunion. This happens when, in the morning, Athena removes Odysseus' disguise, and he re-enters the hut. At this point, Telemachus first does not believe what is before him, thinking that the gods must be tricking him. However, once he is convinced this is father is real, he is happy and excited!
With this, we can see that the answer is "Initially, Telemachus is suspicious that the gods are playing a trick on him, but is soon overjoyed when he realizes that his father has truly returned."