Bit older than yours OP but I took my two camping at the weekend, 1.5 and 2.5. We got a couple of cheap ready beds from Argos and they were fine. The duvets that come with them are paper thin so I just piled their duvets from home and a couple of blankets on them (it was cold!).
The ready bed the youngest went in has a bumper round the top so he couldn’t easily roll out, would prob be OK for a fairly static 8 month old.
If your tent is big enough just take a travel cot, but make sure you put plenty of blankets underneath as well as on top of the baby.
As for noise – there’s usually plenty of other noise on campsites, I wouldn’t be overly bothered if I were you. Try to find a family oriented site and pitch as far away from others as you can. Anyone nearby, have a word before bed time and give them fair warning.
My two were awake at 5am so I had to smuggle them out as quietly as possible, we spent over an hour before breakfast exploring the nearby river and throwing stones.