I'd test him out. Who would you be leaving him with? See is they'll have him a few nights leading up to the wedding to see how he goes.
DS was very attatched to the boob. At 9 months I went out for my birthday & left him with my mum. Mum is very patient & so good with the kids. She wandered around with him outside for 2 hours in the middle of the night when he wouldn't settle!! I had to go get him at 6am though.

After that he's stayed with them at least once a month. He did used to put a hand down mums shirt when half asleep, & the first few months I did have to go pick him up very early morning, but mum just used her amazing patience (that she never had with us!!) & kept going til he slept if I wasn't close enough!