Error 90000 is not the route your ISP is taking. It is, quite literally, the server coming back to you with 'So far as I can tell you're still connected; I'm not letting you have two identical sessions at once.'
Services like Pingzapper will certainly improve your latency, but I seriously doubt it'll totally stop unexpected connection failures on the part of your ISP (especially not completely) because you still have to get out of the most vulnerable part of your ISP's route before they can start doing their job. Though yeah they might protect you from losing your link to the SE datacenter in the rare event a connection way down the line suffers a blip, rather than your whole connection suffering a failure. And it certainly won't make the server not present you with a 90000 if you do suffer a connection failure and thus don't log out of the game properly: error 90000 is an error on the server itself caused by a connection issue.
I'd love to know what error message 10102 indicates though.