I am yet to get a bounce high enough to reach second boost, but I believe it may be possible with enough speed going into it and getting lucky on the bounces.
You do this by just taking as much speed into it as possible and going head first into the corner as low as possible, then turning left while busy bonking to point upwards.
Got a pretty close attempt, can still get more speed there tho. Likely is possible but not sure if it'd be faster.
At this point I'm fairly certain it won't be faster that way, however, I've found that using it to either reach the first corner of the boost or the diagonal part may be. It'll still be barely faster tho. If going straight to second booster is faster, you'd still have to have an insanely good start, which would probably be better used on a solid end rather than on a pretty random bounce. Maybe we can revisit this if it gets super optimised.