I can't find any source for the specific claim in the headline besides extremely generic news churn sites. There's an official WH statement that Biden spoke with Netanyahu by phone and offered Israel 'all appropriate means of support' but this $8 billion number could be entirely made up, it's not attributed even to an anonymous US government official. The US typically gives Israel $3.8bn in military aid annually, and Israel has probably the best0equipped military in the region. I find it unlikely that the US gave more than 2 years of aid at once within hours of a conflict breaking out, and without any acknowledgement from Congress.
https://www.whitehouse.gov/briefing-room/statements-releases...
There's a lot of BS circulating this morning passing itself off as breaking news; probably best to be skeptical.