7 players? Phew, brave soul, brave soul indeed.

But 7 is the limits of my courage anyway I play fast and loose with the rules to speed things up, and for the most part I don't actually have stats for the NPCs (unless they are a nemesis, and then not always) and I just "eyeball" things I use one index card per encounter for initiative tracking and I don't even roll initiative for all the NPCs... I'll roll a bunch and leave all the rest at the end, I use minis (and lots of them) on maps and that's how I track who has and hasn't gone yet in a round. I like to use a lot of one off minions as cannon fodder and if they roll well enough I still let them kill more than one anyway. Like I said fast and loose with the rules but it runs well enough. In previous editions of the game if I hand waved the rules like this it would often break the game but FFG star wars is very "fault tolerant"/forgiving. Maybe I'm also becoming a better GM after all these years.

How do I handle sessions where 1 person couldn't make it. After that session should I still give that character XP? If I don't, I'm afraid of the group becoming lopsided in strengths.

(Right now I'm going to handle the missing person's PC by having someone else roll for them and I'm even thinking about having the missing person's character be there only narratively so that they don't get messed up.)

I give all my players the same xp regardless of whether they attended or not. I grant bonus xp based on cool and innovative solutions to problems and particularly good roleplay.

When a new player enters the game, cameo or recurring, I start them off with close to the same xp as the other players, depending on their role and whether or not I think they'll be more trouble than they are worth.

for the question at hand no show no XP! but this in my mind builds a cool factor in the game. I think this game is fine with a "imbalance of XP" I like having 200 XP PCs with 50 XP PCs. everyone still has a part to play. the game handles it just fine. whether you are negotiating with a hutt cartel or fighting the empire some heroes are more powerful then others. it is not to say that they have more to do but as a good GM all players should roll about the same number of checks each game regardless of the dice pool or XP total. but do what is best for your group at the end of the day but don't let the fear of being "lopsided" put you off, it dos not exists in this game. a low XP PC can still deal 12 damage with a well placed blaster rifle shot regardless of XP!