What are some benefitial ways to deal with attatchment at a daycare?

I'm a 17 year old guy and I've worked at a daycare center for about 7 months and I absolutely love it. I love the kids and they all seem to enjoy my presence and look up to me. However, there is one child, in first or second grade, who seems to be taking it further than the rest. At first he would just jump on me and play rough but It's gotten to a point where today he sat directly at my feet when we were getting ready to go outside, I let him hold my glasses, and he said outloud that, "He let me because I'm his favorite!" and later in the day he chose to hug me from behind instead of playing rough. While this could just be an off day for him, I'm still worried he is growing attatched. While he has grown on me considerably since I first started work (maybe to become a favorite which I feel is understandable) and I treat him well, I still discipline him the same as the other children and I do not spoil him.

In short, how can I deal with potential attatchment while encouraging the development of relationships and without making him feel like I'm rejecting him?