That whining sound that changes pitch with speed is a classic sign of a worn differential bearing rather than wheel bearings. At 90,000 km it’s pretty common, especially if the diff fluid hasn’t been swapped out on schedule. I’d recommend getting it looked at sooner rather than later — a bearing replacement is much cheaper than a full diff rebuild if metal contamination spreads. An independent shop familiar with Dodge/Mopar diffs is usually the better value over the dealership for this kind of job.