One of the points to slow playing a hand is to let the other players catch up a little. Sometimes they catch up a little more than we intend.
I really don't slow play a multi-way pot very much anymore, unless I flop a full house or better. Someone will catch up and pass you if you slow play trips. There's that hidden straight or runner runner flush just waiting to pound you.
I'm probably exagerrating, I probably slow played a flopped straight recently or something that I don't remember.
Especially with a hand like 59o. I figure if I get to keep my blind with a hand like that, I'm ahead. I usually will try to take the pot down right there if I can.
Plus, even when you go fast, the beauty of online poker is that some fish won't believe you and will call anyway. So you knock out at least some players, and get paid by the fishes, when they don't hit their miracles.