We're having the same problem with our 8.5mo (it started about 1.5 months ago). It's not separation anxiety - daddy cares for him during the day, and I'm the one who gets up during the night. He'll wake almost every night at least once somewhere between 1am and 4am. Sometimes he'll go back to sleep with a little shush-pat, other times it takes a few minutes, and then some nights he's standing and wailing and it requires a few rounds of PU/PD.
Last night, of course, ended up being a 2 hour marathon where he just wouldn't settle even after 16+ rounds of PU/PD, DH finally suggested he might be hungry, I fixed a 4oz bottle which vanished, and while I was deciding if I needed to give him more (I'd put him back in his crib) DS finally fell asleep. I just can't keep going on like this. DS's tired from losing sleep each night which he never seems to make up in naps, I'm even more so - I often can't fall back asleep because I'm listening for him - and I'm worried it's becoming a pattern and that he'll get overtired.
We just recently did cold turkey paci removal, because he was starting to reach for it during A periods, and after the first day naps were fine; he's doing more chewing on his lovey, and might be teething (can't feel anything), but he's not in pain because he stops crying the moment I lift him up and starts again the moment I start laying him back down.