Having a 409A valuation is not a prerequisite for raising any kind of capital (including "convertible securities" like convertible notes, SAFE, and KISS) if you do not plan on issuing stock options.
However, if you plan to issue stock options, you will need to do a 409A valuation, regardless of your fundraising status. The 409A valuation is an assessment of the value of your common stock, and is required to set the option exercise price for these stock options.
If you have already done a 409A valuation in the past, you will need an updated valuation after raising a new round of capital (including "convertible securities" like convertible notes, SAFE, and KISS) because a new round of financing is a "material event" that impacts the value of your company.
Check out this article for more information: Step-By-Step Guide to 409A Valuations.
Disclaimer: We are not lawyers, and this is not legal advice. Although we try to make sure our information is accurate and useful, please consult a lawyer if you want legal advice.