Can an individual open a personal (non-business) checking or savings account using an EIN instead of their SSN?
If so, what are the advantages or disadvantages of doing so?
According to IRS Publication 1635, Understanding your EIN (PDF), under "What is an EIN?" on page 2:
Caution: An EIN is for use in connection with your business activities only. Do not use your EIN in place of your social security number (SSN).
As you say your EIN is for your business as a sole proprietor, I would also refer to Publication 334, Tax Guide for Small Business, under "Identification Numbers":
Social security number (SSN). Generally, use your SSN as your taxpayer identification number. You must put this number on each of your individual income tax forms, such as Form 1040 and its schedules.
Employer identification number (EIN). You must also have an EIN to use as a taxpayer identification number if you do either of the following.
Pay wages to one or more employees.
File pension or excise tax returns.
If you must have an EIN, include it along with your SSN on your Schedule C or C-EZ as instructed.
While I can't point to anything specifically about bank accounts, in general the guidance I see is that your SSN is used for your personal stuff, and you have an EIN for use in your business where needed.
You may be able to open a bank account listing the EIN as the taxpayer identification number on the account. I don't believe there's a legal distinction between what makes something a "business" account or not, though a bank may have different account offerings for different purposes, and only offer some of them to entities rather than individuals. If you want to have a separate account for your business transactions, you may want them to open it in the name of your business and they may allow you to use your EIN on it. Whether you can do this for one of their "personal" account offerings would be up to the bank.
I don't see any particular advantages to using your EIN on a bank account for an individual, though, and I could see it causing a bit of confusion with the bank if you're trying to do so in a way that isn't one of their "normal" account types for a business. As a sole proprietor, there really isn't any distinction between you and your business. Any interest income is taxable to you in the same way. But I don't think there's anything stopping you legally other than perhaps your particular bank's policy on such things. I would suggest contacting your bank (or trying several banks) to get more information on what account offerings they have available and what would best fit you and your business's needs.