OK, then.
Now aren’t Catholics obligated to obey and agree with the Catechism that says that muslims and Catholics worship the same god?
No, because paragraph 841 runs counter to (and you're gonna love this) Tradition. The CCC English translation had to be corrected as regards homosexuals already, the correction on what god muslims worship will come eventually... probably after the sacking of Rome, but still.
Above my pay grade.
I would think the real objection is to, “The plan of salvation also includes those who acknowledge the Creator, in the first place amongst whom are the Muslims...”
Plan of salvation? Also? First place?
As to which God, the statement does seem to make a backhanded slap at “these [who] profess to hold the faith of Abraham”. Profess but don’t?
Catholic teaching seems no more definitive than any other denomination.