We didn’t wrap DDs presents that first year. We hid them under a blanket in the sitting room, and after we had fed her breakfast, we let her in and just pulled off the blanket. That worked well, even if she was quite confused at first.
You can get a nice Christmas outfit- an elf or Santa or something nice. A onesie type is more practical (and usually more fun and casual) than a posh “good dress” or good trousers and shirt type outfit. And be prepared that it won’t last (food, poo, someone else spilling something...), so have more nice but clean outfits ready to change into if necessary.
It’s a nice time to start traditions like reading Twas the night before Christmas as a bedtime story on a Christmas Eve. Or getting a decoration for the tree - whether that’s just for the first year or an annual event.
At 8 months, I think dd was starting to “help” baking - would wear her apron and could mix an egg with a fork, or stir flour and cocoa powder together, or spoon sugar into the weighing scale - but under strict supervision and with a helping hand on the fork/spoon (and me being prepared to clear up much messier kitchens afterward). Might be big enough , if they’re doing play doh cutting and rolling play, to roll and cut cookies in the same way. But the results of their efforts are strictly for Mum and Dad, or the bin, and only ones that you do are for visitors.
And just enjoy playing music and dancing round the kitchen together, without expecting it to be magic all the time.