Can they fit a Malibu? Yes. Can they fit your Malibu? You'll be the best person to answer that.My bad. Can I fit camaro tires on the Malibu?
What's your vehicles ride height? Has it been lowered?
Suspension combo?
Current tire size you mentioned was 215/70-14 which calculates to 25.85" tall. The 245/35-20's you mentioned are ~26.75 tall for about a 1" difference in height. You didn't mention what size (width) or back-space/offset for the wheels so we def don't know. You mentioned "too wide" but don't say where? Rubbed on the inside? Stuck out past the sheet-metal?
You need to know the backspace/offset of the Camaro wheels you're interested in. They came w/18's & 20's in 2010 as well as other possible sizes depending on the options the car came with. What Camaro wheel can make a difference. A quick Google search tells me they had some 18x7.5" steel wheels w/245/50-18's @27.64" tall but you'd need to know the back-space/offset to determine if they might fit 'as-is', or if they might fit w/spacers, or if they won't fit. Based on the comment the 245/35-20's wouldn't work, the 18" factory Camaro steel styled wheels that popped up when I googled are almost an inch taller.
As 80/MALIBU/COUPE posted 18's w/decent back-space/offset & within a certain range (tire size) can, will, & do fit.