Most of the yeast foamed out of the tube when I opened it. So I pitched into my starter any way maybe got 10 to 20 % of the yeast into the starter should I still use it?

Yes.

That's exactly why I don't like White Labs and avoid their yeast whenever possible.

If you really lost that much yeast, you may find that your starter takes longer than normal to finish. If it takes more than a 24 to 36 hours, you might consider chilling it to settle the yeast out. You can then see how much you have and decide if you want to pitch that into another starter to continue the propagation.

At least its on a stir plate and its belgian yeast.

You can build from a single colony on a stir plate. Assuming there was no contamination, you'll be fine.

Yes, the foaming yeast can be an issue. I shake my vial to mix in the yeast witht the liquid, then let it sit for while. If you slowly open it, it shouldn't be a problem. It takes more patience than using Wyeast packs, but not really that much more.

I rarely use whitelabs (though I bought 3 yesterday because that's what they had) but I haven't had any foaming issues. I shake mine up before, too.

I think having it plenty cold is a good precaution against it foaming up.
I've never had that issue.