Spending a chunk of office time earlier today setting up the liturgical schedule on the parish calendar, I noted that the Solemnity of the Immaculate Conception falls on Saturday. In my parish, this puts us in a bit of a situation. We don’t celebrate Mass on the Saturday of a given week, though the other parish in town does. We’ll likely offer a Mass. But when? Friday night, maybe before supper? Saturday morning? Our regular weekday Mass is 12 noon.
Your parish may be lucky to have a Saturday Mass. I hope it is well-attended. How will you handle the celebration of the holy day? Music ministry? Treats and snacks? Will any children come with parents? (Or without?)
Sit in the chair and tell us how you would handle it, even to the point of making it obligatory again, despite the Saturday.
Catholic Sensibility 
Unless your bishop has dispensed the obligation, it is a holyday of obligation in the USA, as the patronal solemnity for the nation. The only time it’s not is when it falls on Sunday and the liturgical observance is transferred to Monday, December 9th.
Now, the preceptual observance can be met on Saturday evening Mass (the propers for which are Advent 2, as it ranks higher than IC in the table of precedence), but then one needs to go to another Mass on Sunday (or again later Saturday evening…) to satisfy the precept for Sunday.
Typically, parishes will have anticipated Masses on Friday evening, and more than one on Saturday morning (so…no funerals on Saturday morning, and it would be a good day to avoid other ritual liturgies…).
In any event, if the US had a tradition of patronal observance like old-fashioned Catholic countries, it would be interesting, shall we say.