The line your contact described is roughly right, though the words get used loosely and that's most of your confusion.
An investor portal, strictly, is the LP-facing website. Investors log in and see their position, their documents, their distribution history, and any updates you post. That's a software product, and the cheap end of the market is real software. A few hundred to a couple thousand a year for a single entity with 31 investors is normal.
Fund administration is a service, with people doing work. A fund administrator maintains the capital account for each LP, calculates distributions and the waterfall, produces the statements, coordinates with your CPA on K-1 delivery, and keeps the investor register clean. That's usually priced per fund per year plus something per investor, and it's why the $9k quote exists. Some administrators bundle a portal, which is why their marketing page looks identical to the software-only vendor's page.
So ask each vendor one question: who calculates the distribution amounts? If the answer is "you upload the numbers," it's software. If the answer is "we do, from the operating agreement," it's administration.
The part people usually skip at your size is the investor register itself, meaning the authoritative list of who owns what, with current addresses, tax IDs, banking details, and signed subscription documents attached. If that lives in three inboxes and a spreadsheet, a portal won't fix it, it'll just display it. Clean that up first, then pick the tool. Also confirm in writing whether the portal fee is a fund expense or a sponsor expense under your documents, because LPs notice that line.