Not as far as I know. There are/were buses from Caldercruix-Glasgow (which take several hours), although these may now be in the hands of local bus companies only going as far as Coatbridge, or if you're really lucky, Kirkwood.
There's also plenty of buses from Blackridge in East Lothian (home of Susan Boyle, who will probably be on hand to open the new station given that she's the only person from there to ever acheive... well, anything) to Bathgate and Edinburgh. But, as far as I'm aware, no buses currently run between North Lanarkshire and East Lothian. And, of course, with the train line on the way, any service would likely not be worthwhile. So this really is bridging a gap across all forms of public transport.
PS, the reason you'd be told to go back to Easterhouse is because the 900 bus makes stops there before continuing on the A8 towards Edinburgh. Indeed, this is the last stop before Harthill services and is actually one of the best ways of getting to Edinburgh from Coatbridge at the moment!