男性が「デート」ってどういう意味ですか？?

I'm American, and currently live in America. Recently I went to Japan and met someone there.

He doesn't speak English, though I speak Japanese well enough for it not to be too big of a problem, at least currently. He's always very nice and considerate of me, and will do everything in his power to help me understand something if I don't understand it one hundred percent.

Right before I left, he made a Facebook so that we could keep in contact more easily.

We've been emailing each other generally at least once a day since I've left, though his busy schedule doesn't always allow for it.

I've noticed though that it's sometimes hard to keep a conversation going, since he never initiates one, and doesn't really divulge anything about himself unless I specifically ask.

All of his friends that I've met know that I'm interested in him, so I'm fairly certain he knows as well, though we've never discussed it.

When I told him that I would be going back to Japan for Christmas for some work, he just responded 「楽しみにしているね☆じゃあ、いつデートする？」

A few problems have come from this.

Although I go to Japan for at least a month twice a year, I'm still a University student. I'm trying to study abroad within the next two years, but I won't lie and say the distance doesn't scare me. It also doesn't help that he's almost a decade older than me.

How seriously should I take him? I've been told that the insinuation with a 「デート」　is it could be used in a platonic sense, or romantic sense.

I also think that 告白や付き合うのこと should be done face to face.

And by American standards, he would be considered uninterested for the most part, but some girls have told me that it is a charm to some people. Help would be greatly appreciated!

答えは英語や日本語でも、どっちでもいいです。

お願いしますm(_ _)m