We did that for many years using something like this:
Pelican Boats - Universal Kayak & SUP Car-Top Roof Carrier Kit – PS0481-3 - Fits Vehicles – Heavy Duty & Safe https://www.amazon.com/dp/B07CT4VTBJ/ref=cm_sw_r_apan_glt_fabc_TFCDDQNM66E5FQMAX3ZX
Our local boat store had them and they worked fine. Tied it down with a strap at both ends and ran one through the middle. We finally transitioned to a Thule Hullavator and it was the best purchase ever.
I slapped a pelican argo 100xr on my 2015 fit and my wifes 2013 civic using the foam blocks from canadian tire (yes i am in canada) and from pelican (amazon). this has worked so far (8 trips out). next year i will get something more permanent but for this year with shortages due to covid this was pretty much all that was available.
https://www.amazon.ca/gp/product/B07CT4VTBJ/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
https://www.amazon.ca/gp/product/B00138OMJI/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1
https://www.canadiantire.ca/en/pdp/hood-trunk-tie-down-0792477p.html#srp
https://www.canadiantire.ca/en/pdp/kayak-carrier-kit-0798219p.html#srp