The day we met our DS & DD, we were complete strangers, who spoke another language. The family that they had been staying with in America didn't want to drive an hour to the park that we met the kids at, so they had friends, who had never met the kids, drive them to us. Granted, our kids were 6 yo and 5 yo when we met them. Having only known the people who drove them to us for an hour or so, they were already clinging to them. When they met us, they were scared, but by the time we got to our house, they were clinging to us. The kids just want stability and to feel safe. When we were flying back from Russia with them, post-adoption, there were many families on the plane who had adopted 6 mos to 18 mos. The kids were great, even with a 10 hour flight. I'm sure that once your new son understands that you are there to take care of him and protect him, he will cling to you like glue.
Our son is 8 yo today. It was such an exciting morning in our house and I can't wait to pick them up after work today.
Adoption is amazing. Kids are wonderful. Best of luck as you are opening this next chapter in your lives! I'm so happy for you!