mysticism kabbalah - Playing with non-kosher animals

I have often heard it said that there is a tradition amongst kabbalists not to own, play with or possibly even look at animals that are not kosher. Assuming that this is correct, my question is twofold:

1) I would like a source for this tradition;

2) I would like to know how it is that people deal with the Mishna, Shabbat 9:7. There, Rabbi Yehuda is quoted as noting that people used to give their children dead non-kosher grasshoppers to play with.

Just to be clear, I'm not looking to understand Rabbi Yehuda, whose opinion is not problematic for me. I want to know how religious Jews (might) have dealt with this passage, if it is true that they frown upon coming into contact with impure animals.