if it helps, my DS (8.5 months and VERY clingy) is also going to be at nursery from 10 months. He cries if I so much as leave the room for a few seconds, and won't accept anyone else to settle him to sleep, even DH. Or so I thought...
Last weekend we had a family party to go to, big social pressure to attend. I had to leave DS in a B&B with a babysitter he didn't know. After we'd been at the party for 45 minutes we got the (dreaded / expected) phone call asking us to come back and settle him. By the time I got back to the B&B, 10 minutes away (even in high heeled party shoes, ouch) DS was sitting contented on the babysitters lap, watching telly. No tears, had calmed down immediately she made the phone call. When we got back at 10.30pm it was all the same - he'd woken again but this time settled on babysitters lap no problem at all.
I also left him with my mum for a Saturday morning, for the first time ever 2 weeks ago (family live a long way away, we don't get the chance to leave him with them, I'm not refusing to or anything!) Again, he was great.
If you'd asked me whether this would be possible, I'd have said no way. But it happened.
They can surprise you. I feel lots more confident about the nursery now. Still don't want to go back to work, but thats another story
HTH a bit