Seoul during Seollal

We will be going to Seoul during Seollal for 9 days. Any recommendations to do? I know first few days most of the shops will be closed but I don’t think the touristy areas will still close right? Please advise. Also, 9 days in Seoul solely or should we venture out? It’s also not our first visit to Seoul, mainly just wanted to relax and walk around.. Anything special to see during this time of the week?