To know for sure, you need to:
1. Determine the bolt pattern: Find the bolt pattern for both the Alero rims (likely stamped on the back of the rim itself) and the Malibu's wheel hubs (check your owner's manual or a reliable online source). They need to match exactly. A common pattern is 5x100 or 5x115, but this varies by trim level and year.
2. Check the wheel diameter: The diameter (e.g., 15", 16") should be compatible with the Malibu's wheel wells to avoid rubbing.
3. Compare the offset: The offset is the distance between the mounting surface of the wheel and the centerline of the wheel. A significant difference in offset can cause handling problems or rubbing.
4. Consider the wheel width: Too wide a wheel might not fit the wheel wells or could cause rubbing issues with the suspension or fenders.
In short: Don't assume they'll fit. You *must* verify the bolt pattern, diameter, and offset match before attempting to install the rims. A mismatch could damage your car, and at the very least, won't be safe.